1mod anchor;
   2#[cfg(test)]
   3mod multi_buffer_tests;
   4mod position;
   5
   6pub use anchor::{Anchor, AnchorRangeExt, Offset};
   7pub use position::{TypedOffset, TypedPoint, TypedRow};
   8
   9use anyhow::{Result, anyhow};
  10use buffer_diff::{
  11    BufferDiff, BufferDiffEvent, BufferDiffSnapshot, DiffHunkSecondaryStatus, DiffHunkStatus,
  12    DiffHunkStatusKind,
  13};
  14use clock::ReplicaId;
  15use collections::{BTreeMap, Bound, HashMap, HashSet};
  16use futures::{SinkExt, channel::mpsc};
  17use gpui::{App, AppContext as _, Context, Entity, EntityId, EventEmitter, Task};
  18use itertools::Itertools;
  19use language::{
  20    AutoindentMode, Buffer, BufferChunks, BufferRow, BufferSnapshot, Capability, CharClassifier,
  21    CharKind, Chunk, CursorShape, DiagnosticEntry, DiskState, File, IndentSize, Language,
  22    LanguageScope, OffsetRangeExt, OffsetUtf16, Outline, OutlineItem, Point, PointUtf16, Selection,
  23    TextDimension, TextObject, ToOffset as _, ToPoint as _, TransactionId, TreeSitterOptions,
  24    Unclipped,
  25    language_settings::{IndentGuideSettings, LanguageSettings, language_settings},
  26};
  27
  28use rope::DimensionPair;
  29use smallvec::SmallVec;
  30use smol::future::yield_now;
  31use std::{
  32    any::type_name,
  33    borrow::Cow,
  34    cell::{Cell, Ref, RefCell},
  35    cmp, fmt,
  36    future::Future,
  37    io,
  38    iter::{self, FromIterator},
  39    mem,
  40    ops::{Range, RangeBounds, Sub},
  41    path::Path,
  42    rc::Rc,
  43    str,
  44    sync::Arc,
  45    time::{Duration, Instant},
  46};
  47use sum_tree::{Bias, Cursor, SumTree, TreeMap};
  48use text::{
  49    BufferId, Edit, LineIndent, TextSummary,
  50    locator::Locator,
  51    subscription::{Subscription, Topic},
  52};
  53use theme::SyntaxTheme;
  54use util::post_inc;
  55
  56const NEWLINES: &[u8] = &[b'\n'; u8::MAX as usize];
  57
  58#[derive(Debug, Default, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
  59pub struct ExcerptId(usize);
  60
  61/// One or more [`Buffers`](Buffer) being edited in a single view.
  62///
  63/// See <https://zed.dev/features#multi-buffers>
  64pub struct MultiBuffer {
  65    /// A snapshot of the [`Excerpt`]s in the MultiBuffer.
  66    /// Use [`MultiBuffer::snapshot`] to get a up-to-date snapshot.
  67    snapshot: RefCell<MultiBufferSnapshot>,
  68    /// Contains the state of the buffers being edited
  69    buffers: RefCell<HashMap<BufferId, BufferState>>,
  70    // only used by consumers using `set_excerpts_for_buffer`
  71    excerpts_by_path: BTreeMap<PathKey, Vec<ExcerptId>>,
  72    paths_by_excerpt: HashMap<ExcerptId, PathKey>,
  73    diffs: HashMap<BufferId, DiffState>,
  74    // all_diff_hunks_expanded: bool,
  75    subscriptions: Topic,
  76    /// If true, the multi-buffer only contains a single [`Buffer`] and a single [`Excerpt`]
  77    singleton: bool,
  78    history: History,
  79    title: Option<String>,
  80    capability: Capability,
  81    buffer_changed_since_sync: Rc<Cell<bool>>,
  82}
  83
  84#[derive(Clone, Debug, PartialEq, Eq)]
  85pub enum MultiOrSingleBufferOffsetRange {
  86    Single(Range<usize>),
  87    Multi(Range<usize>),
  88}
  89
  90#[derive(Clone, Debug, PartialEq, Eq)]
  91pub enum Event {
  92    ExcerptsAdded {
  93        buffer: Entity<Buffer>,
  94        predecessor: ExcerptId,
  95        excerpts: Vec<(ExcerptId, ExcerptRange<language::Anchor>)>,
  96    },
  97    ExcerptsRemoved {
  98        ids: Vec<ExcerptId>,
  99    },
 100    ExcerptsExpanded {
 101        ids: Vec<ExcerptId>,
 102    },
 103    ExcerptsEdited {
 104        excerpt_ids: Vec<ExcerptId>,
 105        buffer_ids: Vec<BufferId>,
 106    },
 107    DiffHunksToggled,
 108    Edited {
 109        singleton_buffer_edited: bool,
 110        edited_buffer: Option<Entity<Buffer>>,
 111    },
 112    TransactionUndone {
 113        transaction_id: TransactionId,
 114    },
 115    Reloaded,
 116    ReloadNeeded,
 117
 118    LanguageChanged(BufferId),
 119    CapabilityChanged,
 120    Reparsed(BufferId),
 121    Saved,
 122    FileHandleChanged,
 123    Closed,
 124    Discarded,
 125    DirtyChanged,
 126    DiagnosticsUpdated,
 127    BufferDiffChanged,
 128}
 129
 130/// A diff hunk, representing a range of consequent lines in a multibuffer.
 131#[derive(Debug, Clone, PartialEq, Eq)]
 132pub struct MultiBufferDiffHunk {
 133    /// The row range in the multibuffer where this diff hunk appears.
 134    pub row_range: Range<MultiBufferRow>,
 135    /// The buffer ID that this hunk belongs to.
 136    pub buffer_id: BufferId,
 137    /// The range of the underlying buffer that this hunk corresponds to.
 138    pub buffer_range: Range<text::Anchor>,
 139    /// The excerpt that contains the diff hunk.
 140    pub excerpt_id: ExcerptId,
 141    /// The range within the buffer's diff base that this hunk corresponds to.
 142    pub diff_base_byte_range: Range<usize>,
 143    /// Whether or not this hunk also appears in the 'secondary diff'.
 144    pub secondary_status: DiffHunkSecondaryStatus,
 145}
 146
 147impl MultiBufferDiffHunk {
 148    pub fn status(&self) -> DiffHunkStatus {
 149        let kind = if self.buffer_range.start == self.buffer_range.end {
 150            DiffHunkStatusKind::Deleted
 151        } else if self.diff_base_byte_range.is_empty() {
 152            DiffHunkStatusKind::Added
 153        } else {
 154            DiffHunkStatusKind::Modified
 155        };
 156        DiffHunkStatus {
 157            kind,
 158            secondary: self.secondary_status,
 159        }
 160    }
 161
 162    pub fn is_created_file(&self) -> bool {
 163        self.diff_base_byte_range == (0..0)
 164            && self.buffer_range == (text::Anchor::MIN..text::Anchor::MAX)
 165    }
 166}
 167
 168#[derive(PartialEq, Eq, Ord, PartialOrd, Clone, Hash, Debug)]
 169pub struct PathKey {
 170    namespace: &'static str,
 171    path: Arc<Path>,
 172}
 173
 174impl PathKey {
 175    pub fn namespaced(namespace: &'static str, path: Arc<Path>) -> Self {
 176        Self { namespace, path }
 177    }
 178
 179    pub fn path(&self) -> &Arc<Path> {
 180        &self.path
 181    }
 182}
 183
 184pub type MultiBufferPoint = Point;
 185type ExcerptOffset = TypedOffset<Excerpt>;
 186type ExcerptPoint = TypedPoint<Excerpt>;
 187
 188#[derive(Copy, Clone, Debug, Default, Eq, Ord, PartialOrd, PartialEq, Hash, serde::Deserialize)]
 189#[serde(transparent)]
 190pub struct MultiBufferRow(pub u32);
 191
 192impl MultiBufferRow {
 193    pub const MIN: Self = Self(0);
 194    pub const MAX: Self = Self(u32::MAX);
 195}
 196
 197impl std::ops::Add<usize> for MultiBufferRow {
 198    type Output = Self;
 199
 200    fn add(self, rhs: usize) -> Self::Output {
 201        MultiBufferRow(self.0 + rhs as u32)
 202    }
 203}
 204
 205#[derive(Clone)]
 206struct History {
 207    next_transaction_id: TransactionId,
 208    undo_stack: Vec<Transaction>,
 209    redo_stack: Vec<Transaction>,
 210    transaction_depth: usize,
 211    group_interval: Duration,
 212}
 213
 214#[derive(Clone)]
 215struct Transaction {
 216    id: TransactionId,
 217    buffer_transactions: HashMap<BufferId, text::TransactionId>,
 218    first_edit_at: Instant,
 219    last_edit_at: Instant,
 220    suppress_grouping: bool,
 221}
 222
 223pub trait ToOffset: 'static + fmt::Debug {
 224    fn to_offset(&self, snapshot: &MultiBufferSnapshot) -> usize;
 225}
 226
 227pub trait ToOffsetUtf16: 'static + fmt::Debug {
 228    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16;
 229}
 230
 231pub trait ToPoint: 'static + fmt::Debug {
 232    fn to_point(&self, snapshot: &MultiBufferSnapshot) -> Point;
 233}
 234
 235pub trait ToPointUtf16: 'static + fmt::Debug {
 236    fn to_point_utf16(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16;
 237}
 238
 239struct BufferState {
 240    buffer: Entity<Buffer>,
 241    last_version: clock::Global,
 242    last_non_text_state_update_count: usize,
 243    excerpts: Vec<Locator>,
 244    _subscriptions: [gpui::Subscription; 2],
 245}
 246
 247struct DiffState {
 248    diff: Entity<BufferDiff>,
 249    _subscription: gpui::Subscription,
 250}
 251
 252impl DiffState {
 253    fn new(diff: Entity<BufferDiff>, cx: &mut Context<MultiBuffer>) -> Self {
 254        DiffState {
 255            _subscription: cx.subscribe(&diff, |this, diff, event, cx| match event {
 256                BufferDiffEvent::DiffChanged { changed_range } => {
 257                    if let Some(changed_range) = changed_range.clone() {
 258                        this.buffer_diff_changed(diff, changed_range, cx)
 259                    }
 260                    cx.emit(Event::BufferDiffChanged);
 261                }
 262                BufferDiffEvent::LanguageChanged => this.buffer_diff_language_changed(diff, cx),
 263                _ => {}
 264            }),
 265            diff,
 266        }
 267    }
 268}
 269
 270/// The contents of a [`MultiBuffer`] at a single point in time.
 271#[derive(Clone, Default)]
 272pub struct MultiBufferSnapshot {
 273    singleton: bool,
 274    excerpts: SumTree<Excerpt>,
 275    excerpt_ids: SumTree<ExcerptIdMapping>,
 276    diffs: TreeMap<BufferId, BufferDiffSnapshot>,
 277    diff_transforms: SumTree<DiffTransform>,
 278    replaced_excerpts: TreeMap<ExcerptId, ExcerptId>,
 279    trailing_excerpt_update_count: usize,
 280    all_diff_hunks_expanded: bool,
 281    non_text_state_update_count: usize,
 282    edit_count: usize,
 283    is_dirty: bool,
 284    has_deleted_file: bool,
 285    has_conflict: bool,
 286    show_headers: bool,
 287}
 288
 289#[derive(Debug, Clone)]
 290enum DiffTransform {
 291    BufferContent {
 292        summary: TextSummary,
 293        inserted_hunk_info: Option<DiffTransformHunkInfo>,
 294    },
 295    DeletedHunk {
 296        summary: TextSummary,
 297        buffer_id: BufferId,
 298        hunk_info: DiffTransformHunkInfo,
 299        base_text_byte_range: Range<usize>,
 300        has_trailing_newline: bool,
 301    },
 302}
 303
 304#[derive(Clone, Copy, Debug)]
 305struct DiffTransformHunkInfo {
 306    excerpt_id: ExcerptId,
 307    hunk_start_anchor: text::Anchor,
 308    hunk_secondary_status: DiffHunkSecondaryStatus,
 309}
 310
 311impl Eq for DiffTransformHunkInfo {}
 312
 313impl PartialEq for DiffTransformHunkInfo {
 314    fn eq(&self, other: &DiffTransformHunkInfo) -> bool {
 315        self.excerpt_id == other.excerpt_id && self.hunk_start_anchor == other.hunk_start_anchor
 316    }
 317}
 318
 319impl std::hash::Hash for DiffTransformHunkInfo {
 320    fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
 321        self.excerpt_id.hash(state);
 322        self.hunk_start_anchor.hash(state);
 323    }
 324}
 325
 326#[derive(Clone)]
 327pub struct ExcerptInfo {
 328    pub id: ExcerptId,
 329    pub buffer: BufferSnapshot,
 330    pub buffer_id: BufferId,
 331    pub range: ExcerptRange<text::Anchor>,
 332    pub end_row: MultiBufferRow,
 333}
 334
 335impl std::fmt::Debug for ExcerptInfo {
 336    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 337        f.debug_struct(type_name::<Self>())
 338            .field("id", &self.id)
 339            .field("buffer_id", &self.buffer_id)
 340            .field("path", &self.buffer.file().map(|f| f.path()))
 341            .field("range", &self.range)
 342            .finish()
 343    }
 344}
 345
 346/// A boundary between `Excerpt`s in a [`MultiBuffer`]
 347#[derive(Debug)]
 348pub struct ExcerptBoundary {
 349    pub prev: Option<ExcerptInfo>,
 350    pub next: ExcerptInfo,
 351    /// The row in the `MultiBuffer` where the boundary is located
 352    pub row: MultiBufferRow,
 353}
 354
 355impl ExcerptBoundary {
 356    pub fn starts_new_buffer(&self) -> bool {
 357        match (self.prev.as_ref(), &self.next) {
 358            (None, _) => true,
 359            (Some(prev), next) => prev.buffer_id != next.buffer_id,
 360        }
 361    }
 362}
 363
 364#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 365pub struct ExpandInfo {
 366    pub direction: ExpandExcerptDirection,
 367    pub excerpt_id: ExcerptId,
 368}
 369
 370#[derive(Copy, Clone, Debug, Default, PartialEq, Eq)]
 371pub struct RowInfo {
 372    pub buffer_id: Option<BufferId>,
 373    pub buffer_row: Option<u32>,
 374    pub multibuffer_row: Option<MultiBufferRow>,
 375    pub diff_status: Option<buffer_diff::DiffHunkStatus>,
 376    pub expand_info: Option<ExpandInfo>,
 377}
 378
 379/// A slice into a [`Buffer`] that is being edited in a [`MultiBuffer`].
 380#[derive(Clone)]
 381struct Excerpt {
 382    /// The unique identifier for this excerpt
 383    id: ExcerptId,
 384    /// The location of the excerpt in the [`MultiBuffer`]
 385    locator: Locator,
 386    /// The buffer being excerpted
 387    buffer_id: BufferId,
 388    /// A snapshot of the buffer being excerpted
 389    buffer: BufferSnapshot,
 390    /// The range of the buffer to be shown in the excerpt
 391    range: ExcerptRange<text::Anchor>,
 392    /// The last row in the excerpted slice of the buffer
 393    max_buffer_row: BufferRow,
 394    /// A summary of the text in the excerpt
 395    text_summary: TextSummary,
 396    has_trailing_newline: bool,
 397}
 398
 399/// A public view into an `Excerpt` in a [`MultiBuffer`].
 400///
 401/// Contains methods for getting the [`Buffer`] of the excerpt,
 402/// as well as mapping offsets to/from buffer and multibuffer coordinates.
 403#[derive(Clone)]
 404pub struct MultiBufferExcerpt<'a> {
 405    excerpt: &'a Excerpt,
 406    diff_transforms:
 407        sum_tree::Cursor<'a, DiffTransform, (OutputDimension<usize>, ExcerptDimension<usize>)>,
 408    offset: usize,
 409    excerpt_offset: ExcerptDimension<usize>,
 410    buffer_offset: usize,
 411}
 412
 413#[derive(Clone, Debug)]
 414struct ExcerptIdMapping {
 415    id: ExcerptId,
 416    locator: Locator,
 417}
 418
 419/// A range of text from a single [`Buffer`], to be shown as an `Excerpt`.
 420/// These ranges are relative to the buffer itself
 421#[derive(Clone, Debug, Eq, PartialEq, Hash)]
 422pub struct ExcerptRange<T> {
 423    /// The full range of text to be shown in the excerpt.
 424    pub context: Range<T>,
 425    /// The primary range of text to be highlighted in the excerpt.
 426    /// In a multi-buffer search, this would be the text that matched the search
 427    pub primary: Range<T>,
 428}
 429
 430impl<T: Clone> ExcerptRange<T> {
 431    pub fn new(context: Range<T>) -> Self {
 432        Self {
 433            context: context.clone(),
 434            primary: context,
 435        }
 436    }
 437}
 438
 439#[derive(Clone, Debug, Default)]
 440pub struct ExcerptSummary {
 441    excerpt_id: ExcerptId,
 442    /// The location of the last [`Excerpt`] being summarized
 443    excerpt_locator: Locator,
 444    widest_line_number: u32,
 445    text: TextSummary,
 446}
 447
 448#[derive(Debug, Clone)]
 449pub struct DiffTransformSummary {
 450    input: TextSummary,
 451    output: TextSummary,
 452}
 453
 454#[derive(Clone)]
 455pub struct MultiBufferRows<'a> {
 456    point: Point,
 457    is_empty: bool,
 458    is_singleton: bool,
 459    cursor: MultiBufferCursor<'a, Point>,
 460}
 461
 462pub struct MultiBufferChunks<'a> {
 463    excerpts: Cursor<'a, Excerpt, ExcerptOffset>,
 464    diff_transforms: Cursor<'a, DiffTransform, (usize, ExcerptOffset)>,
 465    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 466    diff_base_chunks: Option<(BufferId, BufferChunks<'a>)>,
 467    buffer_chunk: Option<Chunk<'a>>,
 468    range: Range<usize>,
 469    excerpt_offset_range: Range<ExcerptOffset>,
 470    excerpt_chunks: Option<ExcerptChunks<'a>>,
 471    language_aware: bool,
 472}
 473
 474pub struct ReversedMultiBufferChunks<'a> {
 475    cursor: MultiBufferCursor<'a, usize>,
 476    current_chunks: Option<rope::Chunks<'a>>,
 477    start: usize,
 478    offset: usize,
 479}
 480
 481pub struct MultiBufferBytes<'a> {
 482    range: Range<usize>,
 483    cursor: MultiBufferCursor<'a, usize>,
 484    excerpt_bytes: Option<text::Bytes<'a>>,
 485    has_trailing_newline: bool,
 486    chunk: &'a [u8],
 487}
 488
 489pub struct ReversedMultiBufferBytes<'a> {
 490    range: Range<usize>,
 491    chunks: ReversedMultiBufferChunks<'a>,
 492    chunk: &'a [u8],
 493}
 494
 495#[derive(Clone)]
 496struct MultiBufferCursor<'a, D: TextDimension> {
 497    excerpts: Cursor<'a, Excerpt, ExcerptDimension<D>>,
 498    diff_transforms: Cursor<'a, DiffTransform, (OutputDimension<D>, ExcerptDimension<D>)>,
 499    diffs: &'a TreeMap<BufferId, BufferDiffSnapshot>,
 500    cached_region: Option<MultiBufferRegion<'a, D>>,
 501}
 502
 503#[derive(Clone)]
 504struct MultiBufferRegion<'a, D: TextDimension> {
 505    buffer: &'a BufferSnapshot,
 506    is_main_buffer: bool,
 507    diff_hunk_status: Option<DiffHunkStatus>,
 508    excerpt: &'a Excerpt,
 509    buffer_range: Range<D>,
 510    range: Range<D>,
 511    has_trailing_newline: bool,
 512}
 513
 514struct ExcerptChunks<'a> {
 515    excerpt_id: ExcerptId,
 516    content_chunks: BufferChunks<'a>,
 517    footer_height: usize,
 518}
 519
 520#[derive(Debug)]
 521struct BufferEdit {
 522    range: Range<usize>,
 523    new_text: Arc<str>,
 524    is_insertion: bool,
 525    original_indent_column: Option<u32>,
 526    excerpt_id: ExcerptId,
 527}
 528
 529#[derive(Clone, Copy, Debug, PartialEq)]
 530enum DiffChangeKind {
 531    BufferEdited,
 532    DiffUpdated { base_changed: bool },
 533    ExpandOrCollapseHunks { expand: bool },
 534}
 535
 536#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 537pub enum ExpandExcerptDirection {
 538    Up,
 539    Down,
 540    UpAndDown,
 541}
 542
 543impl ExpandExcerptDirection {
 544    pub fn should_expand_up(&self) -> bool {
 545        match self {
 546            ExpandExcerptDirection::Up => true,
 547            ExpandExcerptDirection::Down => false,
 548            ExpandExcerptDirection::UpAndDown => true,
 549        }
 550    }
 551
 552    pub fn should_expand_down(&self) -> bool {
 553        match self {
 554            ExpandExcerptDirection::Up => false,
 555            ExpandExcerptDirection::Down => true,
 556            ExpandExcerptDirection::UpAndDown => true,
 557        }
 558    }
 559}
 560
 561#[derive(Clone, Debug, PartialEq)]
 562pub struct IndentGuide {
 563    pub buffer_id: BufferId,
 564    pub start_row: MultiBufferRow,
 565    pub end_row: MultiBufferRow,
 566    pub depth: u32,
 567    pub tab_size: u32,
 568    pub settings: IndentGuideSettings,
 569}
 570
 571impl IndentGuide {
 572    pub fn indent_level(&self) -> u32 {
 573        self.depth * self.tab_size
 574    }
 575}
 576
 577impl MultiBuffer {
 578    pub fn new(capability: Capability) -> Self {
 579        Self {
 580            snapshot: RefCell::new(MultiBufferSnapshot {
 581                show_headers: true,
 582                ..MultiBufferSnapshot::default()
 583            }),
 584            buffers: RefCell::default(),
 585            diffs: HashMap::default(),
 586            subscriptions: Topic::default(),
 587            singleton: false,
 588            capability,
 589            title: None,
 590            excerpts_by_path: Default::default(),
 591            paths_by_excerpt: Default::default(),
 592            buffer_changed_since_sync: Default::default(),
 593            history: History {
 594                next_transaction_id: clock::Lamport::default(),
 595                undo_stack: Vec::new(),
 596                redo_stack: Vec::new(),
 597                transaction_depth: 0,
 598                group_interval: Duration::from_millis(300),
 599            },
 600        }
 601    }
 602
 603    pub fn without_headers(capability: Capability) -> Self {
 604        Self {
 605            snapshot: Default::default(),
 606            buffers: Default::default(),
 607            excerpts_by_path: Default::default(),
 608            paths_by_excerpt: Default::default(),
 609            diffs: HashMap::default(),
 610            subscriptions: Default::default(),
 611            singleton: false,
 612            capability,
 613            buffer_changed_since_sync: Default::default(),
 614            history: History {
 615                next_transaction_id: Default::default(),
 616                undo_stack: Default::default(),
 617                redo_stack: Default::default(),
 618                transaction_depth: 0,
 619                group_interval: Duration::from_millis(300),
 620            },
 621            title: Default::default(),
 622        }
 623    }
 624
 625    pub fn clone(&self, new_cx: &mut Context<Self>) -> Self {
 626        let mut buffers = HashMap::default();
 627        let buffer_changed_since_sync = Rc::new(Cell::new(false));
 628        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
 629            buffer_state.buffer.update(new_cx, |buffer, _| {
 630                buffer.record_changes(Rc::downgrade(&buffer_changed_since_sync));
 631            });
 632            buffers.insert(
 633                *buffer_id,
 634                BufferState {
 635                    buffer: buffer_state.buffer.clone(),
 636                    last_version: buffer_state.last_version.clone(),
 637                    last_non_text_state_update_count: buffer_state.last_non_text_state_update_count,
 638                    excerpts: buffer_state.excerpts.clone(),
 639                    _subscriptions: [
 640                        new_cx.observe(&buffer_state.buffer, |_, _, cx| cx.notify()),
 641                        new_cx.subscribe(&buffer_state.buffer, Self::on_buffer_event),
 642                    ],
 643                },
 644            );
 645        }
 646        let mut diff_bases = HashMap::default();
 647        for (buffer_id, diff) in self.diffs.iter() {
 648            diff_bases.insert(*buffer_id, DiffState::new(diff.diff.clone(), new_cx));
 649        }
 650        Self {
 651            snapshot: RefCell::new(self.snapshot.borrow().clone()),
 652            buffers: RefCell::new(buffers),
 653            excerpts_by_path: Default::default(),
 654            paths_by_excerpt: Default::default(),
 655            diffs: diff_bases,
 656            subscriptions: Default::default(),
 657            singleton: self.singleton,
 658            capability: self.capability,
 659            history: self.history.clone(),
 660            title: self.title.clone(),
 661            buffer_changed_since_sync,
 662        }
 663    }
 664
 665    pub fn with_title(mut self, title: String) -> Self {
 666        self.title = Some(title);
 667        self
 668    }
 669
 670    pub fn read_only(&self) -> bool {
 671        self.capability == Capability::ReadOnly
 672    }
 673
 674    pub fn singleton(buffer: Entity<Buffer>, cx: &mut Context<Self>) -> Self {
 675        let mut this = Self::new(buffer.read(cx).capability());
 676        this.singleton = true;
 677        this.push_excerpts(
 678            buffer,
 679            [ExcerptRange::new(text::Anchor::MIN..text::Anchor::MAX)],
 680            cx,
 681        );
 682        this.snapshot.borrow_mut().singleton = true;
 683        this
 684    }
 685
 686    /// Returns an up-to-date snapshot of the MultiBuffer.
 687    pub fn snapshot(&self, cx: &App) -> MultiBufferSnapshot {
 688        self.sync(cx);
 689        self.snapshot.borrow().clone()
 690    }
 691
 692    pub fn read(&self, cx: &App) -> Ref<MultiBufferSnapshot> {
 693        self.sync(cx);
 694        self.snapshot.borrow()
 695    }
 696
 697    pub fn as_singleton(&self) -> Option<Entity<Buffer>> {
 698        if self.singleton {
 699            return Some(
 700                self.buffers
 701                    .borrow()
 702                    .values()
 703                    .next()
 704                    .unwrap()
 705                    .buffer
 706                    .clone(),
 707            );
 708        } else {
 709            None
 710        }
 711    }
 712
 713    pub fn is_singleton(&self) -> bool {
 714        self.singleton
 715    }
 716
 717    pub fn subscribe(&mut self) -> Subscription {
 718        self.subscriptions.subscribe()
 719    }
 720
 721    pub fn is_dirty(&self, cx: &App) -> bool {
 722        self.read(cx).is_dirty()
 723    }
 724
 725    pub fn has_deleted_file(&self, cx: &App) -> bool {
 726        self.read(cx).has_deleted_file()
 727    }
 728
 729    pub fn has_conflict(&self, cx: &App) -> bool {
 730        self.read(cx).has_conflict()
 731    }
 732
 733    // The `is_empty` signature doesn't match what clippy expects
 734    #[allow(clippy::len_without_is_empty)]
 735    pub fn len(&self, cx: &App) -> usize {
 736        self.read(cx).len()
 737    }
 738
 739    pub fn is_empty(&self) -> bool {
 740        self.buffers.borrow().is_empty()
 741    }
 742
 743    pub fn symbols_containing<T: ToOffset>(
 744        &self,
 745        offset: T,
 746        theme: Option<&SyntaxTheme>,
 747        cx: &App,
 748    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
 749        self.read(cx).symbols_containing(offset, theme)
 750    }
 751
 752    pub fn edit<I, S, T>(
 753        &self,
 754        edits: I,
 755        autoindent_mode: Option<AutoindentMode>,
 756        cx: &mut Context<Self>,
 757    ) where
 758        I: IntoIterator<Item = (Range<S>, T)>,
 759        S: ToOffset,
 760        T: Into<Arc<str>>,
 761    {
 762        let snapshot = self.read(cx);
 763        let edits = edits
 764            .into_iter()
 765            .map(|(range, new_text)| {
 766                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
 767                if range.start > range.end {
 768                    mem::swap(&mut range.start, &mut range.end);
 769                }
 770                (range, new_text.into())
 771            })
 772            .collect::<Vec<_>>();
 773
 774        return edit_internal(self, snapshot, edits, autoindent_mode, cx);
 775
 776        // Non-generic part of edit, hoisted out to avoid blowing up LLVM IR.
 777        fn edit_internal(
 778            this: &MultiBuffer,
 779            snapshot: Ref<MultiBufferSnapshot>,
 780            edits: Vec<(Range<usize>, Arc<str>)>,
 781            mut autoindent_mode: Option<AutoindentMode>,
 782            cx: &mut Context<MultiBuffer>,
 783        ) {
 784            if this.read_only() || this.buffers.borrow().is_empty() {
 785                return;
 786            }
 787
 788            let original_indent_columns = match &mut autoindent_mode {
 789                Some(AutoindentMode::Block {
 790                    original_indent_columns,
 791                }) => mem::take(original_indent_columns),
 792                _ => Default::default(),
 793            };
 794
 795            let (buffer_edits, edited_excerpt_ids) =
 796                this.convert_edits_to_buffer_edits(edits, &snapshot, &original_indent_columns);
 797            drop(snapshot);
 798
 799            let mut buffer_ids = Vec::new();
 800            for (buffer_id, mut edits) in buffer_edits {
 801                buffer_ids.push(buffer_id);
 802                edits.sort_by_key(|edit| edit.range.start);
 803                this.buffers.borrow()[&buffer_id]
 804                    .buffer
 805                    .update(cx, |buffer, cx| {
 806                        let mut edits = edits.into_iter().peekable();
 807                        let mut insertions = Vec::new();
 808                        let mut original_indent_columns = Vec::new();
 809                        let mut deletions = Vec::new();
 810                        let empty_str: Arc<str> = Arc::default();
 811                        while let Some(BufferEdit {
 812                            mut range,
 813                            mut new_text,
 814                            mut is_insertion,
 815                            original_indent_column,
 816                            excerpt_id,
 817                        }) = edits.next()
 818                        {
 819                            while let Some(BufferEdit {
 820                                range: next_range,
 821                                is_insertion: next_is_insertion,
 822                                new_text: next_new_text,
 823                                excerpt_id: next_excerpt_id,
 824                                ..
 825                            }) = edits.peek()
 826                            {
 827                                if range.end >= next_range.start {
 828                                    range.end = cmp::max(next_range.end, range.end);
 829                                    is_insertion |= *next_is_insertion;
 830                                    if excerpt_id == *next_excerpt_id {
 831                                        new_text = format!("{new_text}{next_new_text}").into();
 832                                    }
 833                                    edits.next();
 834                                } else {
 835                                    break;
 836                                }
 837                            }
 838
 839                            if is_insertion {
 840                                original_indent_columns.push(original_indent_column);
 841                                insertions.push((
 842                                    buffer.anchor_before(range.start)
 843                                        ..buffer.anchor_before(range.end),
 844                                    new_text.clone(),
 845                                ));
 846                            } else if !range.is_empty() {
 847                                deletions.push((
 848                                    buffer.anchor_before(range.start)
 849                                        ..buffer.anchor_before(range.end),
 850                                    empty_str.clone(),
 851                                ));
 852                            }
 853                        }
 854
 855                        let deletion_autoindent_mode =
 856                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 857                                Some(AutoindentMode::Block {
 858                                    original_indent_columns: Default::default(),
 859                                })
 860                            } else {
 861                                autoindent_mode.clone()
 862                            };
 863                        let insertion_autoindent_mode =
 864                            if let Some(AutoindentMode::Block { .. }) = autoindent_mode {
 865                                Some(AutoindentMode::Block {
 866                                    original_indent_columns,
 867                                })
 868                            } else {
 869                                autoindent_mode.clone()
 870                            };
 871
 872                        buffer.edit(deletions, deletion_autoindent_mode, cx);
 873                        buffer.edit(insertions, insertion_autoindent_mode, cx);
 874                    })
 875            }
 876
 877            cx.emit(Event::ExcerptsEdited {
 878                excerpt_ids: edited_excerpt_ids,
 879                buffer_ids,
 880            });
 881        }
 882    }
 883
 884    fn convert_edits_to_buffer_edits(
 885        &self,
 886        edits: Vec<(Range<usize>, Arc<str>)>,
 887        snapshot: &MultiBufferSnapshot,
 888        original_indent_columns: &[Option<u32>],
 889    ) -> (HashMap<BufferId, Vec<BufferEdit>>, Vec<ExcerptId>) {
 890        let mut buffer_edits: HashMap<BufferId, Vec<BufferEdit>> = Default::default();
 891        let mut edited_excerpt_ids = Vec::new();
 892        let mut cursor = snapshot.cursor::<usize>();
 893        for (ix, (range, new_text)) in edits.into_iter().enumerate() {
 894            let original_indent_column = original_indent_columns.get(ix).copied().flatten();
 895
 896            cursor.seek(&range.start);
 897            let mut start_region = cursor.region().expect("start offset out of bounds");
 898            if !start_region.is_main_buffer {
 899                cursor.next();
 900                if let Some(region) = cursor.region() {
 901                    start_region = region;
 902                } else {
 903                    continue;
 904                }
 905            }
 906
 907            if range.end < start_region.range.start {
 908                continue;
 909            }
 910
 911            if range.end > start_region.range.end {
 912                cursor.seek_forward(&range.end);
 913            }
 914            let mut end_region = cursor.region().expect("end offset out of bounds");
 915            if !end_region.is_main_buffer {
 916                cursor.prev();
 917                if let Some(region) = cursor.region() {
 918                    end_region = region;
 919                } else {
 920                    continue;
 921                }
 922            }
 923
 924            if range.start > end_region.range.end {
 925                continue;
 926            }
 927
 928            let start_overshoot = range.start.saturating_sub(start_region.range.start);
 929            let end_overshoot = range.end.saturating_sub(end_region.range.start);
 930            let buffer_start = (start_region.buffer_range.start + start_overshoot)
 931                .min(start_region.buffer_range.end);
 932            let buffer_end =
 933                (end_region.buffer_range.start + end_overshoot).min(end_region.buffer_range.end);
 934
 935            if start_region.excerpt.id == end_region.excerpt.id {
 936                if start_region.is_main_buffer {
 937                    edited_excerpt_ids.push(start_region.excerpt.id);
 938                    buffer_edits
 939                        .entry(start_region.buffer.remote_id())
 940                        .or_default()
 941                        .push(BufferEdit {
 942                            range: buffer_start..buffer_end,
 943                            new_text,
 944                            is_insertion: true,
 945                            original_indent_column,
 946                            excerpt_id: start_region.excerpt.id,
 947                        });
 948                }
 949            } else {
 950                let start_excerpt_range = buffer_start..start_region.buffer_range.end;
 951                let end_excerpt_range = end_region.buffer_range.start..buffer_end;
 952                if start_region.is_main_buffer {
 953                    edited_excerpt_ids.push(start_region.excerpt.id);
 954                    buffer_edits
 955                        .entry(start_region.buffer.remote_id())
 956                        .or_default()
 957                        .push(BufferEdit {
 958                            range: start_excerpt_range,
 959                            new_text: new_text.clone(),
 960                            is_insertion: true,
 961                            original_indent_column,
 962                            excerpt_id: start_region.excerpt.id,
 963                        });
 964                }
 965                if end_region.is_main_buffer {
 966                    edited_excerpt_ids.push(end_region.excerpt.id);
 967                    buffer_edits
 968                        .entry(end_region.buffer.remote_id())
 969                        .or_default()
 970                        .push(BufferEdit {
 971                            range: end_excerpt_range,
 972                            new_text: new_text.clone(),
 973                            is_insertion: false,
 974                            original_indent_column,
 975                            excerpt_id: end_region.excerpt.id,
 976                        });
 977                }
 978
 979                cursor.seek(&range.start);
 980                cursor.next_excerpt();
 981                while let Some(region) = cursor.region() {
 982                    if region.excerpt.id == end_region.excerpt.id {
 983                        break;
 984                    }
 985                    if region.is_main_buffer {
 986                        edited_excerpt_ids.push(region.excerpt.id);
 987                        buffer_edits
 988                            .entry(region.buffer.remote_id())
 989                            .or_default()
 990                            .push(BufferEdit {
 991                                range: region.buffer_range,
 992                                new_text: new_text.clone(),
 993                                is_insertion: false,
 994                                original_indent_column,
 995                                excerpt_id: region.excerpt.id,
 996                            });
 997                    }
 998                    cursor.next_excerpt();
 999                }
1000            }
1001        }
1002        (buffer_edits, edited_excerpt_ids)
1003    }
1004
1005    pub fn autoindent_ranges<I, S>(&self, ranges: I, cx: &mut Context<Self>)
1006    where
1007        I: IntoIterator<Item = Range<S>>,
1008        S: ToOffset,
1009    {
1010        let snapshot = self.read(cx);
1011        let empty = Arc::<str>::from("");
1012        let edits = ranges
1013            .into_iter()
1014            .map(|range| {
1015                let mut range = range.start.to_offset(&snapshot)..range.end.to_offset(&snapshot);
1016                if range.start > range.end {
1017                    mem::swap(&mut range.start, &mut range.end);
1018                }
1019                (range, empty.clone())
1020            })
1021            .collect::<Vec<_>>();
1022
1023        return autoindent_ranges_internal(self, snapshot, edits, cx);
1024
1025        fn autoindent_ranges_internal(
1026            this: &MultiBuffer,
1027            snapshot: Ref<MultiBufferSnapshot>,
1028            edits: Vec<(Range<usize>, Arc<str>)>,
1029            cx: &mut Context<MultiBuffer>,
1030        ) {
1031            if this.read_only() || this.buffers.borrow().is_empty() {
1032                return;
1033            }
1034
1035            let (buffer_edits, edited_excerpt_ids) =
1036                this.convert_edits_to_buffer_edits(edits, &snapshot, &[]);
1037            drop(snapshot);
1038
1039            let mut buffer_ids = Vec::new();
1040            for (buffer_id, mut edits) in buffer_edits {
1041                buffer_ids.push(buffer_id);
1042                edits.sort_unstable_by_key(|edit| edit.range.start);
1043
1044                let mut ranges: Vec<Range<usize>> = Vec::new();
1045                for edit in edits {
1046                    if let Some(last_range) = ranges.last_mut() {
1047                        if edit.range.start <= last_range.end {
1048                            last_range.end = last_range.end.max(edit.range.end);
1049                            continue;
1050                        }
1051                    }
1052                    ranges.push(edit.range);
1053                }
1054
1055                this.buffers.borrow()[&buffer_id]
1056                    .buffer
1057                    .update(cx, |buffer, cx| {
1058                        buffer.autoindent_ranges(ranges, cx);
1059                    })
1060            }
1061
1062            cx.emit(Event::ExcerptsEdited {
1063                excerpt_ids: edited_excerpt_ids,
1064                buffer_ids,
1065            });
1066        }
1067    }
1068
1069    // Inserts newlines at the given position to create an empty line, returning the start of the new line.
1070    // You can also request the insertion of empty lines above and below the line starting at the returned point.
1071    // Panics if the given position is invalid.
1072    pub fn insert_empty_line(
1073        &mut self,
1074        position: impl ToPoint,
1075        space_above: bool,
1076        space_below: bool,
1077        cx: &mut Context<Self>,
1078    ) -> Point {
1079        let multibuffer_point = position.to_point(&self.read(cx));
1080        let (buffer, buffer_point, _) = self.point_to_buffer_point(multibuffer_point, cx).unwrap();
1081        self.start_transaction(cx);
1082        let empty_line_start = buffer.update(cx, |buffer, cx| {
1083            buffer.insert_empty_line(buffer_point, space_above, space_below, cx)
1084        });
1085        self.end_transaction(cx);
1086        multibuffer_point + (empty_line_start - buffer_point)
1087    }
1088
1089    pub fn start_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1090        self.start_transaction_at(Instant::now(), cx)
1091    }
1092
1093    pub fn start_transaction_at(
1094        &mut self,
1095        now: Instant,
1096        cx: &mut Context<Self>,
1097    ) -> Option<TransactionId> {
1098        if let Some(buffer) = self.as_singleton() {
1099            return buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1100        }
1101
1102        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1103            buffer.update(cx, |buffer, _| buffer.start_transaction_at(now));
1104        }
1105        self.history.start_transaction(now)
1106    }
1107
1108    pub fn last_transaction_id(&self) -> Option<TransactionId> {
1109        let last_transaction = self.history.undo_stack.last()?;
1110        return Some(last_transaction.id);
1111    }
1112
1113    pub fn end_transaction(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1114        self.end_transaction_at(Instant::now(), cx)
1115    }
1116
1117    pub fn end_transaction_at(
1118        &mut self,
1119        now: Instant,
1120        cx: &mut Context<Self>,
1121    ) -> Option<TransactionId> {
1122        if let Some(buffer) = self.as_singleton() {
1123            return buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx));
1124        }
1125
1126        let mut buffer_transactions = HashMap::default();
1127        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1128            if let Some(transaction_id) =
1129                buffer.update(cx, |buffer, cx| buffer.end_transaction_at(now, cx))
1130            {
1131                buffer_transactions.insert(buffer.read(cx).remote_id(), transaction_id);
1132            }
1133        }
1134
1135        if self.history.end_transaction(now, buffer_transactions) {
1136            let transaction_id = self.history.group().unwrap();
1137            Some(transaction_id)
1138        } else {
1139            None
1140        }
1141    }
1142
1143    pub fn edited_ranges_for_transaction<D>(
1144        &self,
1145        transaction_id: TransactionId,
1146        cx: &App,
1147    ) -> Vec<Range<D>>
1148    where
1149        D: TextDimension + Ord + Sub<D, Output = D>,
1150    {
1151        let Some(transaction) = self.history.transaction(transaction_id) else {
1152            return Vec::new();
1153        };
1154
1155        let mut ranges = Vec::new();
1156        let snapshot = self.read(cx);
1157        let buffers = self.buffers.borrow();
1158        let mut cursor = snapshot.excerpts.cursor::<ExcerptSummary>(&());
1159
1160        for (buffer_id, buffer_transaction) in &transaction.buffer_transactions {
1161            let Some(buffer_state) = buffers.get(buffer_id) else {
1162                continue;
1163            };
1164
1165            let buffer = buffer_state.buffer.read(cx);
1166            for range in buffer.edited_ranges_for_transaction_id::<D>(*buffer_transaction) {
1167                for excerpt_id in &buffer_state.excerpts {
1168                    cursor.seek(excerpt_id, Bias::Left, &());
1169                    if let Some(excerpt) = cursor.item() {
1170                        if excerpt.locator == *excerpt_id {
1171                            let excerpt_buffer_start =
1172                                excerpt.range.context.start.summary::<D>(buffer);
1173                            let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(buffer);
1174                            let excerpt_range = excerpt_buffer_start..excerpt_buffer_end;
1175                            if excerpt_range.contains(&range.start)
1176                                && excerpt_range.contains(&range.end)
1177                            {
1178                                let excerpt_start = D::from_text_summary(&cursor.start().text);
1179
1180                                let mut start = excerpt_start;
1181                                start.add_assign(&(range.start - excerpt_buffer_start));
1182                                let mut end = excerpt_start;
1183                                end.add_assign(&(range.end - excerpt_buffer_start));
1184
1185                                ranges.push(start..end);
1186                                break;
1187                            }
1188                        }
1189                    }
1190                }
1191            }
1192        }
1193
1194        ranges.sort_by_key(|range| range.start);
1195        ranges
1196    }
1197
1198    pub fn merge_transactions(
1199        &mut self,
1200        transaction: TransactionId,
1201        destination: TransactionId,
1202        cx: &mut Context<Self>,
1203    ) {
1204        if let Some(buffer) = self.as_singleton() {
1205            buffer.update(cx, |buffer, _| {
1206                buffer.merge_transactions(transaction, destination)
1207            });
1208        } else if let Some(transaction) = self.history.forget(transaction) {
1209            if let Some(destination) = self.history.transaction_mut(destination) {
1210                for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1211                    if let Some(destination_buffer_transaction_id) =
1212                        destination.buffer_transactions.get(&buffer_id)
1213                    {
1214                        if let Some(state) = self.buffers.borrow().get(&buffer_id) {
1215                            state.buffer.update(cx, |buffer, _| {
1216                                buffer.merge_transactions(
1217                                    buffer_transaction_id,
1218                                    *destination_buffer_transaction_id,
1219                                )
1220                            });
1221                        }
1222                    } else {
1223                        destination
1224                            .buffer_transactions
1225                            .insert(buffer_id, buffer_transaction_id);
1226                    }
1227                }
1228            }
1229        }
1230    }
1231
1232    pub fn finalize_last_transaction(&mut self, cx: &mut Context<Self>) {
1233        self.history.finalize_last_transaction();
1234        for BufferState { buffer, .. } in self.buffers.borrow().values() {
1235            buffer.update(cx, |buffer, _| {
1236                buffer.finalize_last_transaction();
1237            });
1238        }
1239    }
1240
1241    pub fn push_transaction<'a, T>(&mut self, buffer_transactions: T, cx: &Context<Self>)
1242    where
1243        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
1244    {
1245        self.history
1246            .push_transaction(buffer_transactions, Instant::now(), cx);
1247        self.history.finalize_last_transaction();
1248    }
1249
1250    pub fn group_until_transaction(
1251        &mut self,
1252        transaction_id: TransactionId,
1253        cx: &mut Context<Self>,
1254    ) {
1255        if let Some(buffer) = self.as_singleton() {
1256            buffer.update(cx, |buffer, _| {
1257                buffer.group_until_transaction(transaction_id)
1258            });
1259        } else {
1260            self.history.group_until(transaction_id);
1261        }
1262    }
1263
1264    pub fn set_active_selections(
1265        &self,
1266        selections: &[Selection<Anchor>],
1267        line_mode: bool,
1268        cursor_shape: CursorShape,
1269        cx: &mut Context<Self>,
1270    ) {
1271        let mut selections_by_buffer: HashMap<BufferId, Vec<Selection<text::Anchor>>> =
1272            Default::default();
1273        let snapshot = self.read(cx);
1274        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1275        for selection in selections {
1276            let start_locator = snapshot.excerpt_locator_for_id(selection.start.excerpt_id);
1277            let end_locator = snapshot.excerpt_locator_for_id(selection.end.excerpt_id);
1278
1279            cursor.seek(&Some(start_locator), Bias::Left, &());
1280            while let Some(excerpt) = cursor.item() {
1281                if excerpt.locator > *end_locator {
1282                    break;
1283                }
1284
1285                let mut start = excerpt.range.context.start;
1286                let mut end = excerpt.range.context.end;
1287                if excerpt.id == selection.start.excerpt_id {
1288                    start = selection.start.text_anchor;
1289                }
1290                if excerpt.id == selection.end.excerpt_id {
1291                    end = selection.end.text_anchor;
1292                }
1293                selections_by_buffer
1294                    .entry(excerpt.buffer_id)
1295                    .or_default()
1296                    .push(Selection {
1297                        id: selection.id,
1298                        start,
1299                        end,
1300                        reversed: selection.reversed,
1301                        goal: selection.goal,
1302                    });
1303
1304                cursor.next(&());
1305            }
1306        }
1307
1308        for (buffer_id, buffer_state) in self.buffers.borrow().iter() {
1309            if !selections_by_buffer.contains_key(buffer_id) {
1310                buffer_state
1311                    .buffer
1312                    .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1313            }
1314        }
1315
1316        for (buffer_id, mut selections) in selections_by_buffer {
1317            self.buffers.borrow()[&buffer_id]
1318                .buffer
1319                .update(cx, |buffer, cx| {
1320                    selections.sort_unstable_by(|a, b| a.start.cmp(&b.start, buffer));
1321                    let mut selections = selections.into_iter().peekable();
1322                    let merged_selections = Arc::from_iter(iter::from_fn(|| {
1323                        let mut selection = selections.next()?;
1324                        while let Some(next_selection) = selections.peek() {
1325                            if selection.end.cmp(&next_selection.start, buffer).is_ge() {
1326                                let next_selection = selections.next().unwrap();
1327                                if next_selection.end.cmp(&selection.end, buffer).is_ge() {
1328                                    selection.end = next_selection.end;
1329                                }
1330                            } else {
1331                                break;
1332                            }
1333                        }
1334                        Some(selection)
1335                    }));
1336                    buffer.set_active_selections(merged_selections, line_mode, cursor_shape, cx);
1337                });
1338        }
1339    }
1340
1341    pub fn remove_active_selections(&self, cx: &mut Context<Self>) {
1342        for buffer in self.buffers.borrow().values() {
1343            buffer
1344                .buffer
1345                .update(cx, |buffer, cx| buffer.remove_active_selections(cx));
1346        }
1347    }
1348
1349    pub fn undo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1350        let mut transaction_id = None;
1351        if let Some(buffer) = self.as_singleton() {
1352            transaction_id = buffer.update(cx, |buffer, cx| buffer.undo(cx));
1353        } else {
1354            while let Some(transaction) = self.history.pop_undo() {
1355                let mut undone = false;
1356                for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1357                    if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1358                        undone |= buffer.update(cx, |buffer, cx| {
1359                            let undo_to = *buffer_transaction_id;
1360                            if let Some(entry) = buffer.peek_undo_stack() {
1361                                *buffer_transaction_id = entry.transaction_id();
1362                            }
1363                            buffer.undo_to_transaction(undo_to, cx)
1364                        });
1365                    }
1366                }
1367
1368                if undone {
1369                    transaction_id = Some(transaction.id);
1370                    break;
1371                }
1372            }
1373        }
1374
1375        if let Some(transaction_id) = transaction_id {
1376            cx.emit(Event::TransactionUndone { transaction_id });
1377        }
1378
1379        transaction_id
1380    }
1381
1382    pub fn redo(&mut self, cx: &mut Context<Self>) -> Option<TransactionId> {
1383        if let Some(buffer) = self.as_singleton() {
1384            return buffer.update(cx, |buffer, cx| buffer.redo(cx));
1385        }
1386
1387        while let Some(transaction) = self.history.pop_redo() {
1388            let mut redone = false;
1389            for (buffer_id, buffer_transaction_id) in &mut transaction.buffer_transactions {
1390                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1391                    redone |= buffer.update(cx, |buffer, cx| {
1392                        let redo_to = *buffer_transaction_id;
1393                        if let Some(entry) = buffer.peek_redo_stack() {
1394                            *buffer_transaction_id = entry.transaction_id();
1395                        }
1396                        buffer.redo_to_transaction(redo_to, cx)
1397                    });
1398                }
1399            }
1400
1401            if redone {
1402                return Some(transaction.id);
1403            }
1404        }
1405
1406        None
1407    }
1408
1409    pub fn undo_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1410        if let Some(buffer) = self.as_singleton() {
1411            buffer.update(cx, |buffer, cx| buffer.undo_transaction(transaction_id, cx));
1412        } else if let Some(transaction) = self.history.remove_from_undo(transaction_id) {
1413            for (buffer_id, transaction_id) in &transaction.buffer_transactions {
1414                if let Some(BufferState { buffer, .. }) = self.buffers.borrow().get(buffer_id) {
1415                    buffer.update(cx, |buffer, cx| {
1416                        buffer.undo_transaction(*transaction_id, cx)
1417                    });
1418                }
1419            }
1420        }
1421    }
1422
1423    pub fn forget_transaction(&mut self, transaction_id: TransactionId, cx: &mut Context<Self>) {
1424        if let Some(buffer) = self.as_singleton() {
1425            buffer.update(cx, |buffer, _| {
1426                buffer.forget_transaction(transaction_id);
1427            });
1428        } else if let Some(transaction) = self.history.forget(transaction_id) {
1429            for (buffer_id, buffer_transaction_id) in transaction.buffer_transactions {
1430                if let Some(state) = self.buffers.borrow_mut().get_mut(&buffer_id) {
1431                    state.buffer.update(cx, |buffer, _| {
1432                        buffer.forget_transaction(buffer_transaction_id);
1433                    });
1434                }
1435            }
1436        }
1437    }
1438
1439    pub fn push_excerpts<O>(
1440        &mut self,
1441        buffer: Entity<Buffer>,
1442        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1443        cx: &mut Context<Self>,
1444    ) -> Vec<ExcerptId>
1445    where
1446        O: text::ToOffset,
1447    {
1448        self.insert_excerpts_after(ExcerptId::max(), buffer, ranges, cx)
1449    }
1450
1451    pub fn push_excerpts_with_context_lines<O>(
1452        &mut self,
1453        buffer: Entity<Buffer>,
1454        ranges: Vec<Range<O>>,
1455        context_line_count: u32,
1456        cx: &mut Context<Self>,
1457    ) -> Vec<Range<Anchor>>
1458    where
1459        O: text::ToPoint + text::ToOffset,
1460    {
1461        let buffer_id = buffer.read(cx).remote_id();
1462        let buffer_snapshot = buffer.read(cx).snapshot();
1463        let (excerpt_ranges, range_counts) =
1464            build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1465
1466        let excerpt_ids = self.push_excerpts(buffer, excerpt_ranges, cx);
1467
1468        let mut anchor_ranges = Vec::new();
1469        let mut ranges = ranges.into_iter();
1470        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(range_counts.into_iter()) {
1471            anchor_ranges.extend(ranges.by_ref().take(range_count).map(|range| {
1472                let start = Anchor {
1473                    buffer_id: Some(buffer_id),
1474                    excerpt_id,
1475                    text_anchor: buffer_snapshot.anchor_after(range.start),
1476                    diff_base_anchor: None,
1477                };
1478                let end = Anchor {
1479                    buffer_id: Some(buffer_id),
1480                    excerpt_id,
1481                    text_anchor: buffer_snapshot.anchor_after(range.end),
1482                    diff_base_anchor: None,
1483                };
1484                start..end
1485            }))
1486        }
1487        anchor_ranges
1488    }
1489
1490    pub fn location_for_path(&self, path: &PathKey, cx: &App) -> Option<Anchor> {
1491        let excerpt_id = self.excerpts_by_path.get(path)?.first()?;
1492        let snapshot = self.snapshot(cx);
1493        let excerpt = snapshot.excerpt(*excerpt_id)?;
1494        Some(Anchor::in_buffer(
1495            *excerpt_id,
1496            excerpt.buffer_id,
1497            excerpt.range.context.start,
1498        ))
1499    }
1500
1501    pub fn excerpt_paths(&self) -> impl Iterator<Item = &PathKey> {
1502        self.excerpts_by_path.keys()
1503    }
1504
1505    fn expand_excerpts_with_paths(
1506        &mut self,
1507        ids: impl IntoIterator<Item = ExcerptId>,
1508        line_count: u32,
1509        direction: ExpandExcerptDirection,
1510        cx: &mut Context<Self>,
1511    ) {
1512        let grouped = ids
1513            .into_iter()
1514            .chunk_by(|id| self.paths_by_excerpt.get(id).cloned())
1515            .into_iter()
1516            .flat_map(|(k, v)| Some((k?, v.into_iter().collect::<Vec<_>>())))
1517            .collect::<Vec<_>>();
1518        let snapshot = self.snapshot(cx);
1519
1520        for (path, ids) in grouped.into_iter() {
1521            let Some(excerpt_ids) = self.excerpts_by_path.get(&path) else {
1522                continue;
1523            };
1524
1525            let ids_to_expand = HashSet::from_iter(ids);
1526            let expanded_ranges = excerpt_ids.iter().filter_map(|excerpt_id| {
1527                let excerpt = snapshot.excerpt(*excerpt_id)?;
1528
1529                let mut context = excerpt.range.context.to_point(&excerpt.buffer);
1530                if ids_to_expand.contains(excerpt_id) {
1531                    match direction {
1532                        ExpandExcerptDirection::Up => {
1533                            context.start.row = context.start.row.saturating_sub(line_count);
1534                            context.start.column = 0;
1535                        }
1536                        ExpandExcerptDirection::Down => {
1537                            context.end.row =
1538                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1539                            context.end.column = excerpt.buffer.line_len(context.end.row);
1540                        }
1541                        ExpandExcerptDirection::UpAndDown => {
1542                            context.start.row = context.start.row.saturating_sub(line_count);
1543                            context.start.column = 0;
1544                            context.end.row =
1545                                (context.end.row + line_count).min(excerpt.buffer.max_point().row);
1546                            context.end.column = excerpt.buffer.line_len(context.end.row);
1547                        }
1548                    }
1549                }
1550
1551                Some(ExcerptRange {
1552                    context,
1553                    primary: excerpt.range.primary.to_point(&excerpt.buffer),
1554                })
1555            });
1556            let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1557            for range in expanded_ranges {
1558                if let Some(last_range) = merged_ranges.last_mut() {
1559                    if last_range.context.end >= range.context.start {
1560                        last_range.context.end = range.context.end;
1561                        continue;
1562                    }
1563                }
1564                merged_ranges.push(range)
1565            }
1566            let Some(excerpt_id) = excerpt_ids.first() else {
1567                continue;
1568            };
1569            let Some(buffer_id) = &snapshot.buffer_id_for_excerpt(*excerpt_id) else {
1570                continue;
1571            };
1572
1573            let Some(buffer) = self
1574                .buffers
1575                .borrow()
1576                .get(buffer_id)
1577                .map(|b| b.buffer.clone())
1578            else {
1579                continue;
1580            };
1581
1582            let buffer_snapshot = buffer.read(cx).snapshot();
1583            self.update_path_excerpts(path.clone(), buffer, &buffer_snapshot, merged_ranges, cx);
1584        }
1585    }
1586
1587    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1588    pub fn set_excerpts_for_path(
1589        &mut self,
1590        path: PathKey,
1591        buffer: Entity<Buffer>,
1592        ranges: Vec<Range<Point>>,
1593        context_line_count: u32,
1594        cx: &mut Context<Self>,
1595    ) -> bool {
1596        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1597
1598        let excerpt_ranges = ranges.into_iter().map(|range| {
1599            let start = range
1600                .start
1601                .saturating_sub(Point::new(context_line_count, 0));
1602            let end_row = (range.end.row + 2).min(buffer_snapshot.max_point().row);
1603            let end = Point::new(end_row, buffer_snapshot.line_len(end_row));
1604            ExcerptRange {
1605                context: start..end,
1606                primary: range,
1607            }
1608        });
1609
1610        let (_, is_new) =
1611            self.set_excerpt_ranges_for_path(path, buffer, excerpt_ranges.collect(), cx);
1612        is_new
1613    }
1614
1615    /// Sets excerpts, returns `true` if at least one new excerpt was added.
1616    pub fn set_excerpt_ranges_for_path(
1617        &mut self,
1618        path: PathKey,
1619        buffer: Entity<Buffer>,
1620        ranges: Vec<ExcerptRange<Point>>,
1621        cx: &mut Context<Self>,
1622    ) -> (Vec<Range<Anchor>>, bool) {
1623        let buffer_snapshot = buffer.update(cx, |buffer, _| buffer.snapshot());
1624
1625        let (new, counts) = self.merge_excerpt_ranges(&ranges);
1626        let (excerpt_ids, added_a_new_excerpt) =
1627            self.update_path_excerpts(path, buffer, &buffer_snapshot, new, cx);
1628
1629        let mut result = Vec::new();
1630        let mut ranges = ranges.into_iter();
1631        for (excerpt_id, range_count) in excerpt_ids.into_iter().zip(counts.into_iter()) {
1632            for range in ranges.by_ref().take(range_count) {
1633                let range = Anchor::range_in_buffer(
1634                    excerpt_id,
1635                    buffer_snapshot.remote_id(),
1636                    buffer_snapshot.anchor_before(&range.primary.start)
1637                        ..buffer_snapshot.anchor_after(&range.primary.end),
1638                );
1639                result.push(range)
1640            }
1641        }
1642        (result, added_a_new_excerpt)
1643    }
1644
1645    fn merge_excerpt_ranges(
1646        &self,
1647        expanded_ranges: &Vec<ExcerptRange<Point>>,
1648    ) -> (Vec<ExcerptRange<Point>>, Vec<usize>) {
1649        let mut merged_ranges: Vec<ExcerptRange<Point>> = Vec::new();
1650        let mut counts: Vec<usize> = Vec::new();
1651        for range in expanded_ranges {
1652            if let Some(last_range) = merged_ranges.last_mut() {
1653                if last_range.context.end >= range.context.start {
1654                    last_range.context.end = range.context.end;
1655                    *counts.last_mut().unwrap() += 1;
1656                    continue;
1657                }
1658            }
1659            merged_ranges.push(range.clone());
1660            counts.push(1);
1661        }
1662        return (merged_ranges, counts);
1663    }
1664
1665    fn update_path_excerpts(
1666        &mut self,
1667        path: PathKey,
1668        buffer: Entity<Buffer>,
1669        buffer_snapshot: &BufferSnapshot,
1670        new: Vec<ExcerptRange<Point>>,
1671        cx: &mut Context<Self>,
1672    ) -> (Vec<ExcerptId>, bool) {
1673        let mut insert_after = self
1674            .excerpts_by_path
1675            .range(..path.clone())
1676            .next_back()
1677            .map(|(_, value)| *value.last().unwrap())
1678            .unwrap_or(ExcerptId::min());
1679
1680        let existing = self
1681            .excerpts_by_path
1682            .get(&path)
1683            .cloned()
1684            .unwrap_or_default();
1685
1686        let mut new_iter = new.into_iter().peekable();
1687        let mut existing_iter = existing.into_iter().peekable();
1688
1689        let mut excerpt_ids = Vec::new();
1690        let mut to_remove = Vec::new();
1691        let mut to_insert: Vec<(ExcerptId, ExcerptRange<Point>)> = Vec::new();
1692        let mut added_a_new_excerpt = false;
1693        let snapshot = self.snapshot(cx);
1694
1695        let mut next_excerpt_id =
1696            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1697                last_entry.id.0 + 1
1698            } else {
1699                1
1700            };
1701
1702        let mut next_excerpt_id = move || ExcerptId(post_inc(&mut next_excerpt_id));
1703
1704        let mut excerpts_cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1705        excerpts_cursor.next(&());
1706
1707        loop {
1708            let (new, existing) = match (new_iter.peek(), existing_iter.peek()) {
1709                (Some(new), Some(existing)) => (new, existing),
1710                (None, None) => break,
1711                (None, Some(_)) => {
1712                    let existing_id = existing_iter.next().unwrap();
1713                    let locator = snapshot.excerpt_locator_for_id(existing_id);
1714                    let existing_excerpt = excerpts_cursor.item().unwrap();
1715                    excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1716                    let existing_end = existing_excerpt
1717                        .range
1718                        .context
1719                        .end
1720                        .to_point(&buffer_snapshot);
1721                    if let Some((new_id, last)) = to_insert.last() {
1722                        if existing_end <= last.context.end {
1723                            self.snapshot
1724                                .borrow_mut()
1725                                .replaced_excerpts
1726                                .insert(existing_id, *new_id);
1727                        }
1728                    }
1729                    to_remove.push(existing_id);
1730                    continue;
1731                }
1732                (Some(_), None) => {
1733                    added_a_new_excerpt = true;
1734                    to_insert.push((next_excerpt_id(), new_iter.next().unwrap()));
1735                    continue;
1736                }
1737            };
1738            let locator = snapshot.excerpt_locator_for_id(*existing);
1739            excerpts_cursor.seek_forward(&Some(locator), Bias::Left, &());
1740            let Some(existing_excerpt) = excerpts_cursor.item() else {
1741                to_remove.push(existing_iter.next().unwrap());
1742                to_insert.push((next_excerpt_id(), new_iter.next().unwrap()));
1743                continue;
1744            };
1745            if existing_excerpt.buffer_id != buffer_snapshot.remote_id() {
1746                to_remove.push(existing_iter.next().unwrap());
1747                to_insert.push((next_excerpt_id(), new_iter.next().unwrap()));
1748                continue;
1749            }
1750
1751            let existing_start = existing_excerpt
1752                .range
1753                .context
1754                .start
1755                .to_point(&buffer_snapshot);
1756            let existing_end = existing_excerpt
1757                .range
1758                .context
1759                .end
1760                .to_point(&buffer_snapshot);
1761
1762            if existing_end < new.context.start {
1763                let existing_id = existing_iter.next().unwrap();
1764                if let Some((new_id, last)) = to_insert.last() {
1765                    if existing_end <= last.context.end {
1766                        self.snapshot
1767                            .borrow_mut()
1768                            .replaced_excerpts
1769                            .insert(existing_id, *new_id);
1770                    }
1771                }
1772                to_remove.push(existing_id);
1773                continue;
1774            } else if existing_start > new.context.end {
1775                to_insert.push((next_excerpt_id(), new_iter.next().unwrap()));
1776                continue;
1777            }
1778
1779            if existing_start == new.context.start && existing_end == new.context.end {
1780                excerpt_ids.extend(to_insert.iter().map(|(id, _)| id));
1781                self.insert_excerpts_with_ids_after(
1782                    insert_after,
1783                    buffer.clone(),
1784                    mem::take(&mut to_insert),
1785                    cx,
1786                );
1787                insert_after = existing_iter.next().unwrap();
1788                excerpt_ids.push(insert_after);
1789                new_iter.next();
1790            } else {
1791                let existing_id = existing_iter.next().unwrap();
1792                let new_id = next_excerpt_id();
1793                self.snapshot
1794                    .borrow_mut()
1795                    .replaced_excerpts
1796                    .insert(existing_id, new_id);
1797                to_remove.push(existing_id);
1798                let mut range = new_iter.next().unwrap();
1799                range.context.start = range.context.start.min(existing_start);
1800                range.context.end = range.context.end.max(existing_end);
1801                to_insert.push((new_id, range));
1802            }
1803        }
1804
1805        excerpt_ids.extend(to_insert.iter().map(|(id, _)| id));
1806        self.insert_excerpts_with_ids_after(insert_after, buffer, to_insert, cx);
1807        self.remove_excerpts(to_remove, cx);
1808        if excerpt_ids.is_empty() {
1809            self.excerpts_by_path.remove(&path);
1810        } else {
1811            for excerpt_id in &excerpt_ids {
1812                self.paths_by_excerpt.insert(*excerpt_id, path.clone());
1813            }
1814            self.excerpts_by_path.insert(path, excerpt_ids.clone());
1815        }
1816
1817        (excerpt_ids, added_a_new_excerpt)
1818    }
1819
1820    pub fn paths(&self) -> impl Iterator<Item = PathKey> + '_ {
1821        self.excerpts_by_path.keys().cloned()
1822    }
1823
1824    pub fn remove_excerpts_for_path(&mut self, path: PathKey, cx: &mut Context<Self>) {
1825        if let Some(to_remove) = self.excerpts_by_path.remove(&path) {
1826            self.remove_excerpts(to_remove, cx)
1827        }
1828    }
1829
1830    pub fn push_multiple_excerpts_with_context_lines(
1831        &self,
1832        buffers_with_ranges: Vec<(Entity<Buffer>, Vec<Range<text::Anchor>>)>,
1833        context_line_count: u32,
1834        cx: &mut Context<Self>,
1835    ) -> Task<Vec<Range<Anchor>>> {
1836        use futures::StreamExt;
1837
1838        let (excerpt_ranges_tx, mut excerpt_ranges_rx) = mpsc::channel(256);
1839
1840        let mut buffer_ids = Vec::with_capacity(buffers_with_ranges.len());
1841
1842        for (buffer, ranges) in buffers_with_ranges {
1843            let (buffer_id, buffer_snapshot) =
1844                buffer.update(cx, |buffer, _| (buffer.remote_id(), buffer.snapshot()));
1845
1846            buffer_ids.push(buffer_id);
1847
1848            cx.background_spawn({
1849                let mut excerpt_ranges_tx = excerpt_ranges_tx.clone();
1850
1851                async move {
1852                    let (excerpt_ranges, counts) =
1853                        build_excerpt_ranges(&buffer_snapshot, &ranges, context_line_count);
1854                    excerpt_ranges_tx
1855                        .send((buffer_id, buffer.clone(), ranges, excerpt_ranges, counts))
1856                        .await
1857                        .ok();
1858                }
1859            })
1860            .detach()
1861        }
1862
1863        cx.spawn(async move |this, cx| {
1864            let mut results_by_buffer_id = HashMap::default();
1865            while let Some((buffer_id, buffer, ranges, excerpt_ranges, range_counts)) =
1866                excerpt_ranges_rx.next().await
1867            {
1868                results_by_buffer_id
1869                    .insert(buffer_id, (buffer, ranges, excerpt_ranges, range_counts));
1870            }
1871
1872            let mut multi_buffer_ranges = Vec::default();
1873            'outer: for buffer_id in buffer_ids {
1874                let Some((buffer, ranges, excerpt_ranges, range_counts)) =
1875                    results_by_buffer_id.remove(&buffer_id)
1876                else {
1877                    continue;
1878                };
1879
1880                let mut ranges = ranges.into_iter();
1881                let mut range_counts = range_counts.into_iter();
1882                for excerpt_ranges in excerpt_ranges.chunks(100) {
1883                    let excerpt_ids = match this.update(cx, |this, cx| {
1884                        this.push_excerpts(buffer.clone(), excerpt_ranges.iter().cloned(), cx)
1885                    }) {
1886                        Ok(excerpt_ids) => excerpt_ids,
1887                        Err(_) => continue 'outer,
1888                    };
1889
1890                    for (excerpt_id, range_count) in
1891                        excerpt_ids.into_iter().zip(range_counts.by_ref())
1892                    {
1893                        for range in ranges.by_ref().take(range_count) {
1894                            let start = Anchor {
1895                                buffer_id: Some(buffer_id),
1896                                excerpt_id,
1897                                text_anchor: range.start,
1898                                diff_base_anchor: None,
1899                            };
1900                            let end = Anchor {
1901                                buffer_id: Some(buffer_id),
1902                                excerpt_id,
1903                                text_anchor: range.end,
1904                                diff_base_anchor: None,
1905                            };
1906                            multi_buffer_ranges.push(start..end);
1907                        }
1908                    }
1909                }
1910            }
1911
1912            multi_buffer_ranges
1913        })
1914    }
1915
1916    pub fn insert_excerpts_after<O>(
1917        &mut self,
1918        prev_excerpt_id: ExcerptId,
1919        buffer: Entity<Buffer>,
1920        ranges: impl IntoIterator<Item = ExcerptRange<O>>,
1921        cx: &mut Context<Self>,
1922    ) -> Vec<ExcerptId>
1923    where
1924        O: text::ToOffset,
1925    {
1926        let mut ids = Vec::new();
1927        let mut next_excerpt_id =
1928            if let Some(last_entry) = self.snapshot.borrow().excerpt_ids.last() {
1929                last_entry.id.0 + 1
1930            } else {
1931                1
1932            };
1933        self.insert_excerpts_with_ids_after(
1934            prev_excerpt_id,
1935            buffer,
1936            ranges.into_iter().map(|range| {
1937                let id = ExcerptId(post_inc(&mut next_excerpt_id));
1938                ids.push(id);
1939                (id, range)
1940            }),
1941            cx,
1942        );
1943        ids
1944    }
1945
1946    pub fn insert_excerpts_with_ids_after<O>(
1947        &mut self,
1948        prev_excerpt_id: ExcerptId,
1949        buffer: Entity<Buffer>,
1950        ranges: impl IntoIterator<Item = (ExcerptId, ExcerptRange<O>)>,
1951        cx: &mut Context<Self>,
1952    ) where
1953        O: text::ToOffset,
1954    {
1955        assert_eq!(self.history.transaction_depth, 0);
1956        let mut ranges = ranges.into_iter().peekable();
1957        if ranges.peek().is_none() {
1958            return Default::default();
1959        }
1960
1961        self.sync(cx);
1962
1963        let buffer_snapshot = buffer.read(cx).snapshot();
1964        let buffer_id = buffer_snapshot.remote_id();
1965
1966        let mut buffers = self.buffers.borrow_mut();
1967        let buffer_state = buffers.entry(buffer_id).or_insert_with(|| {
1968            self.buffer_changed_since_sync.replace(true);
1969            buffer.update(cx, |buffer, _| {
1970                buffer.record_changes(Rc::downgrade(&self.buffer_changed_since_sync));
1971            });
1972            BufferState {
1973                last_version: buffer_snapshot.version().clone(),
1974                last_non_text_state_update_count: buffer_snapshot.non_text_state_update_count(),
1975                excerpts: Default::default(),
1976                _subscriptions: [
1977                    cx.observe(&buffer, |_, _, cx| cx.notify()),
1978                    cx.subscribe(&buffer, Self::on_buffer_event),
1979                ],
1980                buffer: buffer.clone(),
1981            }
1982        });
1983
1984        let mut snapshot = self.snapshot.borrow_mut();
1985
1986        let mut prev_locator = snapshot.excerpt_locator_for_id(prev_excerpt_id).clone();
1987        let mut new_excerpt_ids = mem::take(&mut snapshot.excerpt_ids);
1988        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
1989        let mut new_excerpts = cursor.slice(&prev_locator, Bias::Right, &());
1990        prev_locator = cursor.start().unwrap_or(Locator::min_ref()).clone();
1991
1992        let edit_start = ExcerptOffset::new(new_excerpts.summary().text.len);
1993        new_excerpts.update_last(
1994            |excerpt| {
1995                excerpt.has_trailing_newline = true;
1996            },
1997            &(),
1998        );
1999
2000        let next_locator = if let Some(excerpt) = cursor.item() {
2001            excerpt.locator.clone()
2002        } else {
2003            Locator::max()
2004        };
2005
2006        let mut excerpts = Vec::new();
2007        while let Some((id, range)) = ranges.next() {
2008            let locator = Locator::between(&prev_locator, &next_locator);
2009            if let Err(ix) = buffer_state.excerpts.binary_search(&locator) {
2010                buffer_state.excerpts.insert(ix, locator.clone());
2011            }
2012            let range = ExcerptRange {
2013                context: buffer_snapshot.anchor_before(&range.context.start)
2014                    ..buffer_snapshot.anchor_after(&range.context.end),
2015                primary: buffer_snapshot.anchor_before(&range.primary.start)
2016                    ..buffer_snapshot.anchor_after(&range.primary.end),
2017            };
2018            excerpts.push((id, range.clone()));
2019            let excerpt = Excerpt::new(
2020                id,
2021                locator.clone(),
2022                buffer_id,
2023                buffer_snapshot.clone(),
2024                range,
2025                ranges.peek().is_some() || cursor.item().is_some(),
2026            );
2027            new_excerpts.push(excerpt, &());
2028            prev_locator = locator.clone();
2029
2030            if let Some(last_mapping_entry) = new_excerpt_ids.last() {
2031                assert!(id > last_mapping_entry.id, "excerpt ids must be increasing");
2032            }
2033            new_excerpt_ids.push(ExcerptIdMapping { id, locator }, &());
2034        }
2035
2036        let edit_end = ExcerptOffset::new(new_excerpts.summary().text.len);
2037
2038        let suffix = cursor.suffix(&());
2039        let changed_trailing_excerpt = suffix.is_empty();
2040        new_excerpts.append(suffix, &());
2041        drop(cursor);
2042        snapshot.excerpts = new_excerpts;
2043        snapshot.excerpt_ids = new_excerpt_ids;
2044        if changed_trailing_excerpt {
2045            snapshot.trailing_excerpt_update_count += 1;
2046        }
2047
2048        self.sync_diff_transforms(
2049            &mut snapshot,
2050            vec![Edit {
2051                old: edit_start..edit_start,
2052                new: edit_start..edit_end,
2053            }],
2054            DiffChangeKind::BufferEdited,
2055        );
2056        cx.emit(Event::Edited {
2057            singleton_buffer_edited: false,
2058            edited_buffer: None,
2059        });
2060        cx.emit(Event::ExcerptsAdded {
2061            buffer,
2062            predecessor: prev_excerpt_id,
2063            excerpts,
2064        });
2065        cx.notify();
2066    }
2067
2068    pub fn clear(&mut self, cx: &mut Context<Self>) {
2069        self.sync(cx);
2070        let ids = self.excerpt_ids();
2071        self.buffers.borrow_mut().clear();
2072        let mut snapshot = self.snapshot.borrow_mut();
2073        let start = ExcerptOffset::new(0);
2074        let prev_len = ExcerptOffset::new(snapshot.excerpts.summary().text.len);
2075        snapshot.excerpts = Default::default();
2076        snapshot.trailing_excerpt_update_count += 1;
2077        snapshot.is_dirty = false;
2078        snapshot.has_deleted_file = false;
2079        snapshot.has_conflict = false;
2080
2081        self.sync_diff_transforms(
2082            &mut snapshot,
2083            vec![Edit {
2084                old: start..prev_len,
2085                new: start..start,
2086            }],
2087            DiffChangeKind::BufferEdited,
2088        );
2089        cx.emit(Event::Edited {
2090            singleton_buffer_edited: false,
2091            edited_buffer: None,
2092        });
2093        cx.emit(Event::ExcerptsRemoved { ids });
2094        cx.notify();
2095    }
2096
2097    pub fn excerpts_for_buffer(
2098        &self,
2099        buffer_id: BufferId,
2100        cx: &App,
2101    ) -> Vec<(ExcerptId, ExcerptRange<text::Anchor>)> {
2102        let mut excerpts = Vec::new();
2103        let snapshot = self.read(cx);
2104        let buffers = self.buffers.borrow();
2105        let mut cursor = snapshot.excerpts.cursor::<Option<&Locator>>(&());
2106        for locator in buffers
2107            .get(&buffer_id)
2108            .map(|state| &state.excerpts)
2109            .into_iter()
2110            .flatten()
2111        {
2112            cursor.seek_forward(&Some(locator), Bias::Left, &());
2113            if let Some(excerpt) = cursor.item() {
2114                if excerpt.locator == *locator {
2115                    excerpts.push((excerpt.id, excerpt.range.clone()));
2116                }
2117            }
2118        }
2119
2120        excerpts
2121    }
2122
2123    pub fn excerpt_ranges_for_buffer(&self, buffer_id: BufferId, cx: &App) -> Vec<Range<Point>> {
2124        let snapshot = self.read(cx);
2125        let buffers = self.buffers.borrow();
2126        let mut excerpts = snapshot
2127            .excerpts
2128            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
2129        let mut diff_transforms = snapshot
2130            .diff_transforms
2131            .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
2132        diff_transforms.next(&());
2133        let locators = buffers
2134            .get(&buffer_id)
2135            .into_iter()
2136            .flat_map(|state| &state.excerpts);
2137        let mut result = Vec::new();
2138        for locator in locators {
2139            excerpts.seek_forward(&Some(locator), Bias::Left, &());
2140            if let Some(excerpt) = excerpts.item() {
2141                if excerpt.locator == *locator {
2142                    let excerpt_start = excerpts.start().1.clone();
2143                    let excerpt_end =
2144                        ExcerptDimension(excerpt_start.0 + excerpt.text_summary.lines);
2145
2146                    diff_transforms.seek_forward(&excerpt_start, Bias::Left, &());
2147                    let overshoot = excerpt_start.0 - diff_transforms.start().0.0;
2148                    let start = diff_transforms.start().1.0 + overshoot;
2149
2150                    diff_transforms.seek_forward(&excerpt_end, Bias::Right, &());
2151                    let overshoot = excerpt_end.0 - diff_transforms.start().0.0;
2152                    let end = diff_transforms.start().1.0 + overshoot;
2153
2154                    result.push(start..end)
2155                }
2156            }
2157        }
2158        result
2159    }
2160
2161    pub fn excerpt_buffer_ids(&self) -> Vec<BufferId> {
2162        self.snapshot
2163            .borrow()
2164            .excerpts
2165            .iter()
2166            .map(|entry| entry.buffer_id)
2167            .collect()
2168    }
2169
2170    pub fn excerpt_ids(&self) -> Vec<ExcerptId> {
2171        self.snapshot
2172            .borrow()
2173            .excerpts
2174            .iter()
2175            .map(|entry| entry.id)
2176            .collect()
2177    }
2178
2179    pub fn excerpt_containing(
2180        &self,
2181        position: impl ToOffset,
2182        cx: &App,
2183    ) -> Option<(ExcerptId, Entity<Buffer>, Range<text::Anchor>)> {
2184        let snapshot = self.read(cx);
2185        let offset = position.to_offset(&snapshot);
2186
2187        let mut cursor = snapshot.cursor::<usize>();
2188        cursor.seek(&offset);
2189        cursor
2190            .excerpt()
2191            .or_else(|| snapshot.excerpts.last())
2192            .map(|excerpt| {
2193                (
2194                    excerpt.id,
2195                    self.buffers
2196                        .borrow()
2197                        .get(&excerpt.buffer_id)
2198                        .unwrap()
2199                        .buffer
2200                        .clone(),
2201                    excerpt.range.context.clone(),
2202                )
2203            })
2204    }
2205
2206    // If point is at the end of the buffer, the last excerpt is returned
2207    pub fn point_to_buffer_offset<T: ToOffset>(
2208        &self,
2209        point: T,
2210        cx: &App,
2211    ) -> Option<(Entity<Buffer>, usize)> {
2212        let snapshot = self.read(cx);
2213        let (buffer, offset) = snapshot.point_to_buffer_offset(point)?;
2214        Some((
2215            self.buffers
2216                .borrow()
2217                .get(&buffer.remote_id())?
2218                .buffer
2219                .clone(),
2220            offset,
2221        ))
2222    }
2223
2224    // If point is at the end of the buffer, the last excerpt is returned
2225    pub fn point_to_buffer_point<T: ToPoint>(
2226        &self,
2227        point: T,
2228        cx: &App,
2229    ) -> Option<(Entity<Buffer>, Point, ExcerptId)> {
2230        let snapshot = self.read(cx);
2231        let (buffer, point, is_main_buffer) =
2232            snapshot.point_to_buffer_point(point.to_point(&snapshot))?;
2233        Some((
2234            self.buffers
2235                .borrow()
2236                .get(&buffer.remote_id())?
2237                .buffer
2238                .clone(),
2239            point,
2240            is_main_buffer,
2241        ))
2242    }
2243
2244    pub fn buffer_point_to_anchor(
2245        &self,
2246        buffer: &Entity<Buffer>,
2247        point: Point,
2248        cx: &App,
2249    ) -> Option<Anchor> {
2250        let mut found = None;
2251        let snapshot = buffer.read(cx).snapshot();
2252        for (excerpt_id, range) in self.excerpts_for_buffer(snapshot.remote_id(), cx) {
2253            let start = range.context.start.to_point(&snapshot);
2254            let end = range.context.end.to_point(&snapshot);
2255            if start <= point && point < end {
2256                found = Some((snapshot.clip_point(point, Bias::Left), excerpt_id));
2257                break;
2258            }
2259            if point < start {
2260                found = Some((start, excerpt_id));
2261            }
2262            if point > end {
2263                found = Some((end, excerpt_id));
2264            }
2265        }
2266
2267        found.map(|(point, excerpt_id)| {
2268            let text_anchor = snapshot.anchor_after(point);
2269            Anchor::in_buffer(excerpt_id, snapshot.remote_id(), text_anchor)
2270        })
2271    }
2272
2273    pub fn remove_excerpts(
2274        &mut self,
2275        excerpt_ids: impl IntoIterator<Item = ExcerptId>,
2276        cx: &mut Context<Self>,
2277    ) {
2278        self.sync(cx);
2279        let ids = excerpt_ids.into_iter().collect::<Vec<_>>();
2280        if ids.is_empty() {
2281            return;
2282        }
2283
2284        let mut buffers = self.buffers.borrow_mut();
2285        let mut snapshot = self.snapshot.borrow_mut();
2286        let mut new_excerpts = SumTree::default();
2287        let mut cursor = snapshot
2288            .excerpts
2289            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2290        let mut edits = Vec::new();
2291        let mut excerpt_ids = ids.iter().copied().peekable();
2292        let mut removed_buffer_ids = Vec::new();
2293
2294        while let Some(excerpt_id) = excerpt_ids.next() {
2295            self.paths_by_excerpt.remove(&excerpt_id);
2296            // Seek to the next excerpt to remove, preserving any preceding excerpts.
2297            let locator = snapshot.excerpt_locator_for_id(excerpt_id);
2298            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
2299
2300            if let Some(mut excerpt) = cursor.item() {
2301                if excerpt.id != excerpt_id {
2302                    continue;
2303                }
2304                let mut old_start = cursor.start().1;
2305
2306                // Skip over the removed excerpt.
2307                'remove_excerpts: loop {
2308                    if let Some(buffer_state) = buffers.get_mut(&excerpt.buffer_id) {
2309                        buffer_state.excerpts.retain(|l| l != &excerpt.locator);
2310                        if buffer_state.excerpts.is_empty() {
2311                            log::debug!(
2312                                "removing buffer and diff for buffer {}",
2313                                excerpt.buffer_id
2314                            );
2315                            buffers.remove(&excerpt.buffer_id);
2316                            removed_buffer_ids.push(excerpt.buffer_id);
2317                        }
2318                    }
2319                    cursor.next(&());
2320
2321                    // Skip over any subsequent excerpts that are also removed.
2322                    if let Some(&next_excerpt_id) = excerpt_ids.peek() {
2323                        let next_locator = snapshot.excerpt_locator_for_id(next_excerpt_id);
2324                        if let Some(next_excerpt) = cursor.item() {
2325                            if next_excerpt.locator == *next_locator {
2326                                excerpt_ids.next();
2327                                excerpt = next_excerpt;
2328                                continue 'remove_excerpts;
2329                            }
2330                        }
2331                    }
2332
2333                    break;
2334                }
2335
2336                // When removing the last excerpt, remove the trailing newline from
2337                // the previous excerpt.
2338                if cursor.item().is_none() && old_start.value > 0 {
2339                    old_start.value -= 1;
2340                    new_excerpts.update_last(|e| e.has_trailing_newline = false, &());
2341                }
2342
2343                // Push an edit for the removal of this run of excerpts.
2344                let old_end = cursor.start().1;
2345                let new_start = ExcerptOffset::new(new_excerpts.summary().text.len);
2346                edits.push(Edit {
2347                    old: old_start..old_end,
2348                    new: new_start..new_start,
2349                });
2350            }
2351        }
2352        let suffix = cursor.suffix(&());
2353        let changed_trailing_excerpt = suffix.is_empty();
2354        new_excerpts.append(suffix, &());
2355        drop(cursor);
2356        snapshot.excerpts = new_excerpts;
2357        for buffer_id in removed_buffer_ids {
2358            self.diffs.remove(&buffer_id);
2359            snapshot.diffs.remove(&buffer_id);
2360        }
2361
2362        if changed_trailing_excerpt {
2363            snapshot.trailing_excerpt_update_count += 1;
2364        }
2365
2366        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2367        self.buffer_changed_since_sync.replace(true);
2368        cx.emit(Event::Edited {
2369            singleton_buffer_edited: false,
2370            edited_buffer: None,
2371        });
2372        cx.emit(Event::ExcerptsRemoved { ids });
2373        cx.notify();
2374    }
2375
2376    pub fn wait_for_anchors<'a, Anchors: 'a + Iterator<Item = Anchor>>(
2377        &self,
2378        anchors: Anchors,
2379        cx: &mut Context<Self>,
2380    ) -> impl 'static + Future<Output = Result<()>> + use<Anchors> {
2381        let borrow = self.buffers.borrow();
2382        let mut error = None;
2383        let mut futures = Vec::new();
2384        for anchor in anchors {
2385            if let Some(buffer_id) = anchor.buffer_id {
2386                if let Some(buffer) = borrow.get(&buffer_id) {
2387                    buffer.buffer.update(cx, |buffer, _| {
2388                        futures.push(buffer.wait_for_anchors([anchor.text_anchor]))
2389                    });
2390                } else {
2391                    error = Some(anyhow!(
2392                        "buffer {buffer_id} is not part of this multi-buffer"
2393                    ));
2394                    break;
2395                }
2396            }
2397        }
2398        async move {
2399            if let Some(error) = error {
2400                Err(error)?;
2401            }
2402            for future in futures {
2403                future.await?;
2404            }
2405            Ok(())
2406        }
2407    }
2408
2409    pub fn text_anchor_for_position<T: ToOffset>(
2410        &self,
2411        position: T,
2412        cx: &App,
2413    ) -> Option<(Entity<Buffer>, language::Anchor)> {
2414        let snapshot = self.read(cx);
2415        let anchor = snapshot.anchor_before(position);
2416        let buffer = self
2417            .buffers
2418            .borrow()
2419            .get(&anchor.buffer_id?)?
2420            .buffer
2421            .clone();
2422        Some((buffer, anchor.text_anchor))
2423    }
2424
2425    fn on_buffer_event(
2426        &mut self,
2427        buffer: Entity<Buffer>,
2428        event: &language::BufferEvent,
2429        cx: &mut Context<Self>,
2430    ) {
2431        cx.emit(match event {
2432            language::BufferEvent::Edited => Event::Edited {
2433                singleton_buffer_edited: true,
2434                edited_buffer: Some(buffer.clone()),
2435            },
2436            language::BufferEvent::DirtyChanged => Event::DirtyChanged,
2437            language::BufferEvent::Saved => Event::Saved,
2438            language::BufferEvent::FileHandleChanged => Event::FileHandleChanged,
2439            language::BufferEvent::Reloaded => Event::Reloaded,
2440            language::BufferEvent::ReloadNeeded => Event::ReloadNeeded,
2441            language::BufferEvent::LanguageChanged => {
2442                Event::LanguageChanged(buffer.read(cx).remote_id())
2443            }
2444            language::BufferEvent::Reparsed => Event::Reparsed(buffer.read(cx).remote_id()),
2445            language::BufferEvent::DiagnosticsUpdated => Event::DiagnosticsUpdated,
2446            language::BufferEvent::Closed => Event::Closed,
2447            language::BufferEvent::Discarded => Event::Discarded,
2448            language::BufferEvent::CapabilityChanged => {
2449                self.capability = buffer.read(cx).capability();
2450                Event::CapabilityChanged
2451            }
2452            language::BufferEvent::Operation { .. } => return,
2453        });
2454    }
2455
2456    fn buffer_diff_language_changed(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2457        self.sync(cx);
2458        let mut snapshot = self.snapshot.borrow_mut();
2459        let diff = diff.read(cx);
2460        let buffer_id = diff.buffer_id;
2461        let diff = diff.snapshot(cx);
2462        snapshot.diffs.insert(buffer_id, diff);
2463    }
2464
2465    fn buffer_diff_changed(
2466        &mut self,
2467        diff: Entity<BufferDiff>,
2468        range: Range<text::Anchor>,
2469        cx: &mut Context<Self>,
2470    ) {
2471        self.sync(cx);
2472        self.buffer_changed_since_sync.replace(true);
2473
2474        let diff = diff.read(cx);
2475        let buffer_id = diff.buffer_id;
2476        let buffers = self.buffers.borrow();
2477        let Some(buffer_state) = buffers.get(&buffer_id) else {
2478            return;
2479        };
2480
2481        let buffer = buffer_state.buffer.read(cx);
2482        let diff_change_range = range.to_offset(buffer);
2483
2484        let new_diff = diff.snapshot(cx);
2485        let mut snapshot = self.snapshot.borrow_mut();
2486        let base_text_changed = snapshot
2487            .diffs
2488            .get(&buffer_id)
2489            .map_or(true, |old_diff| !new_diff.base_texts_eq(old_diff));
2490
2491        snapshot.diffs.insert(buffer_id, new_diff);
2492
2493        let mut excerpt_edits = Vec::new();
2494        for locator in &buffer_state.excerpts {
2495            let mut cursor = snapshot
2496                .excerpts
2497                .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2498            cursor.seek_forward(&Some(locator), Bias::Left, &());
2499            if let Some(excerpt) = cursor.item() {
2500                if excerpt.locator == *locator {
2501                    let excerpt_buffer_range = excerpt.range.context.to_offset(&excerpt.buffer);
2502                    if diff_change_range.end < excerpt_buffer_range.start
2503                        || diff_change_range.start > excerpt_buffer_range.end
2504                    {
2505                        continue;
2506                    }
2507                    let excerpt_start = cursor.start().1;
2508                    let excerpt_len = ExcerptOffset::new(excerpt.text_summary.len);
2509                    let diff_change_start_in_excerpt = ExcerptOffset::new(
2510                        diff_change_range
2511                            .start
2512                            .saturating_sub(excerpt_buffer_range.start),
2513                    );
2514                    let diff_change_end_in_excerpt = ExcerptOffset::new(
2515                        diff_change_range
2516                            .end
2517                            .saturating_sub(excerpt_buffer_range.start),
2518                    );
2519                    let edit_start = excerpt_start + diff_change_start_in_excerpt.min(excerpt_len);
2520                    let edit_end = excerpt_start + diff_change_end_in_excerpt.min(excerpt_len);
2521                    excerpt_edits.push(Edit {
2522                        old: edit_start..edit_end,
2523                        new: edit_start..edit_end,
2524                    });
2525                }
2526            }
2527        }
2528
2529        self.sync_diff_transforms(
2530            &mut snapshot,
2531            excerpt_edits,
2532            DiffChangeKind::DiffUpdated {
2533                base_changed: base_text_changed,
2534            },
2535        );
2536        cx.emit(Event::Edited {
2537            singleton_buffer_edited: false,
2538            edited_buffer: None,
2539        });
2540    }
2541
2542    pub fn all_buffers(&self) -> HashSet<Entity<Buffer>> {
2543        self.buffers
2544            .borrow()
2545            .values()
2546            .map(|state| state.buffer.clone())
2547            .collect()
2548    }
2549
2550    pub fn buffer(&self, buffer_id: BufferId) -> Option<Entity<Buffer>> {
2551        self.buffers
2552            .borrow()
2553            .get(&buffer_id)
2554            .map(|state| state.buffer.clone())
2555    }
2556
2557    pub fn language_at<T: ToOffset>(&self, point: T, cx: &App) -> Option<Arc<Language>> {
2558        self.point_to_buffer_offset(point, cx)
2559            .and_then(|(buffer, offset)| buffer.read(cx).language_at(offset))
2560    }
2561
2562    pub fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
2563        let buffer_id = self
2564            .snapshot
2565            .borrow()
2566            .excerpts
2567            .first()
2568            .map(|excerpt| excerpt.buffer.remote_id());
2569        buffer_id
2570            .and_then(|buffer_id| self.buffer(buffer_id))
2571            .map(|buffer| {
2572                let buffer = buffer.read(cx);
2573                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx)
2574            })
2575            .unwrap_or_else(move || self.language_settings_at(0, cx))
2576    }
2577
2578    pub fn language_settings_at<'a, T: ToOffset>(
2579        &'a self,
2580        point: T,
2581        cx: &'a App,
2582    ) -> Cow<'a, LanguageSettings> {
2583        let mut language = None;
2584        let mut file = None;
2585        if let Some((buffer, offset)) = self.point_to_buffer_offset(point, cx) {
2586            let buffer = buffer.read(cx);
2587            language = buffer.language_at(offset);
2588            file = buffer.file();
2589        }
2590        language_settings(language.map(|l| l.name()), file, cx)
2591    }
2592
2593    pub fn for_each_buffer(&self, mut f: impl FnMut(&Entity<Buffer>)) {
2594        self.buffers
2595            .borrow()
2596            .values()
2597            .for_each(|state| f(&state.buffer))
2598    }
2599
2600    pub fn title<'a>(&'a self, cx: &'a App) -> Cow<'a, str> {
2601        if let Some(title) = self.title.as_ref() {
2602            return title.into();
2603        }
2604
2605        if let Some(buffer) = self.as_singleton() {
2606            if let Some(file) = buffer.read(cx).file() {
2607                return file.file_name(cx).to_string_lossy();
2608            }
2609        }
2610
2611        "untitled".into()
2612    }
2613
2614    pub fn set_title(&mut self, title: String, cx: &mut Context<Self>) {
2615        self.title = Some(title);
2616        cx.notify();
2617    }
2618
2619    /// Preserve preview tabs containing this multibuffer until additional edits occur.
2620    pub fn refresh_preview(&self, cx: &mut Context<Self>) {
2621        for buffer_state in self.buffers.borrow().values() {
2622            buffer_state
2623                .buffer
2624                .update(cx, |buffer, _cx| buffer.refresh_preview());
2625        }
2626    }
2627
2628    /// Whether we should preserve the preview status of a tab containing this multi-buffer.
2629    pub fn preserve_preview(&self, cx: &App) -> bool {
2630        self.buffers
2631            .borrow()
2632            .values()
2633            .all(|state| state.buffer.read(cx).preserve_preview())
2634    }
2635
2636    #[cfg(any(test, feature = "test-support"))]
2637    pub fn is_parsing(&self, cx: &App) -> bool {
2638        self.as_singleton().unwrap().read(cx).is_parsing()
2639    }
2640
2641    pub fn add_diff(&mut self, diff: Entity<BufferDiff>, cx: &mut Context<Self>) {
2642        let buffer_id = diff.read(cx).buffer_id;
2643        self.buffer_diff_changed(diff.clone(), text::Anchor::MIN..text::Anchor::MAX, cx);
2644        self.diffs.insert(buffer_id, DiffState::new(diff, cx));
2645    }
2646
2647    pub fn diff_for(&self, buffer_id: BufferId) -> Option<Entity<BufferDiff>> {
2648        self.diffs.get(&buffer_id).map(|state| state.diff.clone())
2649    }
2650
2651    pub fn expand_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2652        self.expand_or_collapse_diff_hunks(ranges, true, cx);
2653    }
2654
2655    pub fn collapse_diff_hunks(&mut self, ranges: Vec<Range<Anchor>>, cx: &mut Context<Self>) {
2656        self.expand_or_collapse_diff_hunks(ranges, false, cx);
2657    }
2658
2659    pub fn set_all_diff_hunks_expanded(&mut self, cx: &mut Context<Self>) {
2660        self.snapshot.borrow_mut().all_diff_hunks_expanded = true;
2661        self.expand_or_collapse_diff_hunks(vec![Anchor::min()..Anchor::max()], true, cx);
2662    }
2663
2664    pub fn all_diff_hunks_expanded(&self) -> bool {
2665        self.snapshot.borrow().all_diff_hunks_expanded
2666    }
2667
2668    pub fn has_multiple_hunks(&self, cx: &App) -> bool {
2669        self.read(cx)
2670            .diff_hunks_in_range(Anchor::min()..Anchor::max())
2671            .nth(1)
2672            .is_some()
2673    }
2674
2675    pub fn single_hunk_is_expanded(&self, range: Range<Anchor>, cx: &App) -> bool {
2676        let snapshot = self.read(cx);
2677        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2678        let offset_range = range.to_offset(&snapshot);
2679        cursor.seek(&offset_range.start, Bias::Left, &());
2680        while let Some(item) = cursor.item() {
2681            if *cursor.start() >= offset_range.end && *cursor.start() > offset_range.start {
2682                break;
2683            }
2684            if item.hunk_info().is_some() {
2685                return true;
2686            }
2687            cursor.next(&());
2688        }
2689        false
2690    }
2691
2692    pub fn has_expanded_diff_hunks_in_ranges(&self, ranges: &[Range<Anchor>], cx: &App) -> bool {
2693        let snapshot = self.read(cx);
2694        let mut cursor = snapshot.diff_transforms.cursor::<usize>(&());
2695        for range in ranges {
2696            let range = range.to_point(&snapshot);
2697            let start = snapshot.point_to_offset(Point::new(range.start.row, 0));
2698            let end = snapshot.point_to_offset(Point::new(range.end.row + 1, 0));
2699            let start = start.saturating_sub(1);
2700            let end = snapshot.len().min(end + 1);
2701            cursor.seek(&start, Bias::Right, &());
2702            while let Some(item) = cursor.item() {
2703                if *cursor.start() >= end {
2704                    break;
2705                }
2706                if item.hunk_info().is_some() {
2707                    return true;
2708                }
2709                cursor.next(&());
2710            }
2711        }
2712        false
2713    }
2714
2715    pub fn expand_or_collapse_diff_hunks_inner(
2716        &mut self,
2717        ranges: impl IntoIterator<Item = (Range<Point>, ExcerptId)>,
2718        expand: bool,
2719        cx: &mut Context<Self>,
2720    ) {
2721        if self.snapshot.borrow().all_diff_hunks_expanded && !expand {
2722            return;
2723        }
2724        self.sync(cx);
2725        let mut snapshot = self.snapshot.borrow_mut();
2726        let mut excerpt_edits = Vec::new();
2727        for (range, end_excerpt_id) in ranges {
2728            for diff_hunk in snapshot.diff_hunks_in_range(range) {
2729                if diff_hunk.excerpt_id.cmp(&end_excerpt_id, &snapshot).is_gt() {
2730                    continue;
2731                }
2732                let start = Anchor::in_buffer(
2733                    diff_hunk.excerpt_id,
2734                    diff_hunk.buffer_id,
2735                    diff_hunk.buffer_range.start,
2736                );
2737                let end = Anchor::in_buffer(
2738                    diff_hunk.excerpt_id,
2739                    diff_hunk.buffer_id,
2740                    diff_hunk.buffer_range.end,
2741                );
2742                let start = snapshot.excerpt_offset_for_anchor(&start);
2743                let end = snapshot.excerpt_offset_for_anchor(&end);
2744                excerpt_edits.push(text::Edit {
2745                    old: start..end,
2746                    new: start..end,
2747                });
2748            }
2749        }
2750
2751        self.sync_diff_transforms(
2752            &mut snapshot,
2753            excerpt_edits,
2754            DiffChangeKind::ExpandOrCollapseHunks { expand },
2755        );
2756        cx.emit(Event::DiffHunksToggled);
2757        cx.emit(Event::Edited {
2758            singleton_buffer_edited: false,
2759            edited_buffer: None,
2760        });
2761    }
2762
2763    pub fn expand_or_collapse_diff_hunks(
2764        &mut self,
2765        ranges: Vec<Range<Anchor>>,
2766        expand: bool,
2767        cx: &mut Context<Self>,
2768    ) {
2769        let snapshot = self.snapshot.borrow().clone();
2770        let ranges = ranges.iter().map(move |range| {
2771            let end_excerpt_id = range.end.excerpt_id;
2772            let range = range.to_point(&snapshot);
2773            let mut peek_end = range.end;
2774            if range.end.row < snapshot.max_row().0 {
2775                peek_end = Point::new(range.end.row + 1, 0);
2776            };
2777            (range.start..peek_end, end_excerpt_id)
2778        });
2779        self.expand_or_collapse_diff_hunks_inner(ranges, expand, cx);
2780    }
2781
2782    pub fn resize_excerpt(
2783        &mut self,
2784        id: ExcerptId,
2785        range: Range<text::Anchor>,
2786        cx: &mut Context<Self>,
2787    ) {
2788        self.sync(cx);
2789
2790        let mut snapshot = self.snapshot.borrow_mut();
2791        let locator = snapshot.excerpt_locator_for_id(id);
2792        let mut new_excerpts = SumTree::default();
2793        let mut cursor = snapshot
2794            .excerpts
2795            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2796        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2797
2798        let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2799        new_excerpts.append(prefix, &());
2800
2801        let mut excerpt = cursor.item().unwrap().clone();
2802        let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2803
2804        excerpt.range.context.start = range.start;
2805        excerpt.range.context.end = range.end;
2806        excerpt.max_buffer_row = range.end.to_point(&excerpt.buffer).row;
2807
2808        excerpt.text_summary = excerpt
2809            .buffer
2810            .text_summary_for_range(excerpt.range.context.clone());
2811
2812        let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2813        let old_start_offset = cursor.start().1;
2814        let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2815        let edit = Edit {
2816            old: old_start_offset..old_start_offset + old_text_len,
2817            new: new_start_offset..new_start_offset + new_text_len,
2818        };
2819
2820        if let Some(last_edit) = edits.last_mut() {
2821            if last_edit.old.end == edit.old.start {
2822                last_edit.old.end = edit.old.end;
2823                last_edit.new.end = edit.new.end;
2824            } else {
2825                edits.push(edit);
2826            }
2827        } else {
2828            edits.push(edit);
2829        }
2830
2831        new_excerpts.push(excerpt, &());
2832
2833        cursor.next(&());
2834
2835        new_excerpts.append(cursor.suffix(&()), &());
2836
2837        drop(cursor);
2838        snapshot.excerpts = new_excerpts;
2839
2840        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2841        cx.emit(Event::Edited {
2842            singleton_buffer_edited: false,
2843            edited_buffer: None,
2844        });
2845        cx.emit(Event::ExcerptsExpanded { ids: vec![id] });
2846        cx.notify();
2847    }
2848
2849    pub fn expand_excerpts(
2850        &mut self,
2851        ids: impl IntoIterator<Item = ExcerptId>,
2852        line_count: u32,
2853        direction: ExpandExcerptDirection,
2854        cx: &mut Context<Self>,
2855    ) {
2856        if line_count == 0 {
2857            return;
2858        }
2859        self.sync(cx);
2860        if !self.excerpts_by_path.is_empty() {
2861            self.expand_excerpts_with_paths(ids, line_count, direction, cx);
2862            return;
2863        }
2864        let mut snapshot = self.snapshot.borrow_mut();
2865
2866        let ids = ids.into_iter().collect::<Vec<_>>();
2867        let locators = snapshot.excerpt_locators_for_ids(ids.iter().copied());
2868        let mut new_excerpts = SumTree::default();
2869        let mut cursor = snapshot
2870            .excerpts
2871            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
2872        let mut edits = Vec::<Edit<ExcerptOffset>>::new();
2873
2874        for locator in &locators {
2875            let prefix = cursor.slice(&Some(locator), Bias::Left, &());
2876            new_excerpts.append(prefix, &());
2877
2878            let mut excerpt = cursor.item().unwrap().clone();
2879            let old_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2880
2881            let up_line_count = if direction.should_expand_up() {
2882                line_count
2883            } else {
2884                0
2885            };
2886
2887            let start_row = excerpt
2888                .range
2889                .context
2890                .start
2891                .to_point(&excerpt.buffer)
2892                .row
2893                .saturating_sub(up_line_count);
2894            let start_point = Point::new(start_row, 0);
2895            excerpt.range.context.start = excerpt.buffer.anchor_before(start_point);
2896
2897            let down_line_count = if direction.should_expand_down() {
2898                line_count
2899            } else {
2900                0
2901            };
2902
2903            let mut end_point = excerpt.buffer.clip_point(
2904                excerpt.range.context.end.to_point(&excerpt.buffer)
2905                    + Point::new(down_line_count, 0),
2906                Bias::Left,
2907            );
2908            end_point.column = excerpt.buffer.line_len(end_point.row);
2909            excerpt.range.context.end = excerpt.buffer.anchor_after(end_point);
2910            excerpt.max_buffer_row = end_point.row;
2911
2912            excerpt.text_summary = excerpt
2913                .buffer
2914                .text_summary_for_range(excerpt.range.context.clone());
2915
2916            let new_start_offset = ExcerptOffset::new(new_excerpts.summary().text.len);
2917            let old_start_offset = cursor.start().1;
2918            let new_text_len = ExcerptOffset::new(excerpt.text_summary.len);
2919            let edit = Edit {
2920                old: old_start_offset..old_start_offset + old_text_len,
2921                new: new_start_offset..new_start_offset + new_text_len,
2922            };
2923
2924            if let Some(last_edit) = edits.last_mut() {
2925                if last_edit.old.end == edit.old.start {
2926                    last_edit.old.end = edit.old.end;
2927                    last_edit.new.end = edit.new.end;
2928                } else {
2929                    edits.push(edit);
2930                }
2931            } else {
2932                edits.push(edit);
2933            }
2934
2935            new_excerpts.push(excerpt, &());
2936
2937            cursor.next(&());
2938        }
2939
2940        new_excerpts.append(cursor.suffix(&()), &());
2941
2942        drop(cursor);
2943        snapshot.excerpts = new_excerpts;
2944
2945        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
2946        cx.emit(Event::Edited {
2947            singleton_buffer_edited: false,
2948            edited_buffer: None,
2949        });
2950        cx.emit(Event::ExcerptsExpanded { ids });
2951        cx.notify();
2952    }
2953
2954    fn sync(&self, cx: &App) {
2955        let changed = self.buffer_changed_since_sync.replace(false);
2956        if !changed {
2957            return;
2958        }
2959
2960        let mut snapshot = self.snapshot.borrow_mut();
2961        let mut excerpts_to_edit = Vec::new();
2962        let mut non_text_state_updated = false;
2963        let mut is_dirty = false;
2964        let mut has_deleted_file = false;
2965        let mut has_conflict = false;
2966        let mut edited = false;
2967        let mut buffers = self.buffers.borrow_mut();
2968        for buffer_state in buffers.values_mut() {
2969            let buffer = buffer_state.buffer.read(cx);
2970            let version = buffer.version();
2971            let non_text_state_update_count = buffer.non_text_state_update_count();
2972
2973            let buffer_edited = version.changed_since(&buffer_state.last_version);
2974            let buffer_non_text_state_updated =
2975                non_text_state_update_count > buffer_state.last_non_text_state_update_count;
2976            if buffer_edited || buffer_non_text_state_updated {
2977                buffer_state.last_version = version;
2978                buffer_state.last_non_text_state_update_count = non_text_state_update_count;
2979                excerpts_to_edit.extend(
2980                    buffer_state
2981                        .excerpts
2982                        .iter()
2983                        .map(|locator| (locator, buffer_state.buffer.clone(), buffer_edited)),
2984                );
2985            }
2986
2987            edited |= buffer_edited;
2988            non_text_state_updated |= buffer_non_text_state_updated;
2989            is_dirty |= buffer.is_dirty();
2990            has_deleted_file |= buffer
2991                .file()
2992                .map_or(false, |file| file.disk_state() == DiskState::Deleted);
2993            has_conflict |= buffer.has_conflict();
2994        }
2995        if edited {
2996            snapshot.edit_count += 1;
2997        }
2998        if non_text_state_updated {
2999            snapshot.non_text_state_update_count += 1;
3000        }
3001        snapshot.is_dirty = is_dirty;
3002        snapshot.has_deleted_file = has_deleted_file;
3003        snapshot.has_conflict = has_conflict;
3004
3005        for (id, diff) in self.diffs.iter() {
3006            if snapshot.diffs.get(&id).is_none() {
3007                snapshot.diffs.insert(*id, diff.diff.read(cx).snapshot(cx));
3008            }
3009        }
3010
3011        excerpts_to_edit.sort_unstable_by_key(|(locator, _, _)| *locator);
3012
3013        let mut edits = Vec::new();
3014        let mut new_excerpts = SumTree::default();
3015        let mut cursor = snapshot
3016            .excerpts
3017            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
3018
3019        for (locator, buffer, buffer_edited) in excerpts_to_edit {
3020            new_excerpts.append(cursor.slice(&Some(locator), Bias::Left, &()), &());
3021            let old_excerpt = cursor.item().unwrap();
3022            let buffer = buffer.read(cx);
3023            let buffer_id = buffer.remote_id();
3024
3025            let mut new_excerpt;
3026            if buffer_edited {
3027                edits.extend(
3028                    buffer
3029                        .edits_since_in_range::<usize>(
3030                            old_excerpt.buffer.version(),
3031                            old_excerpt.range.context.clone(),
3032                        )
3033                        .map(|edit| {
3034                            let excerpt_old_start = cursor.start().1;
3035                            let excerpt_new_start =
3036                                ExcerptOffset::new(new_excerpts.summary().text.len);
3037                            let old_start = excerpt_old_start + ExcerptOffset::new(edit.old.start);
3038                            let old_end = excerpt_old_start + ExcerptOffset::new(edit.old.end);
3039                            let new_start = excerpt_new_start + ExcerptOffset::new(edit.new.start);
3040                            let new_end = excerpt_new_start + ExcerptOffset::new(edit.new.end);
3041                            Edit {
3042                                old: old_start..old_end,
3043                                new: new_start..new_end,
3044                            }
3045                        }),
3046                );
3047
3048                new_excerpt = Excerpt::new(
3049                    old_excerpt.id,
3050                    locator.clone(),
3051                    buffer_id,
3052                    buffer.snapshot(),
3053                    old_excerpt.range.clone(),
3054                    old_excerpt.has_trailing_newline,
3055                );
3056            } else {
3057                new_excerpt = old_excerpt.clone();
3058                new_excerpt.buffer = buffer.snapshot();
3059            }
3060
3061            new_excerpts.push(new_excerpt, &());
3062            cursor.next(&());
3063        }
3064        new_excerpts.append(cursor.suffix(&()), &());
3065
3066        drop(cursor);
3067        snapshot.excerpts = new_excerpts;
3068
3069        self.sync_diff_transforms(&mut snapshot, edits, DiffChangeKind::BufferEdited);
3070    }
3071
3072    fn sync_diff_transforms(
3073        &self,
3074        snapshot: &mut MultiBufferSnapshot,
3075        excerpt_edits: Vec<text::Edit<ExcerptOffset>>,
3076        change_kind: DiffChangeKind,
3077    ) {
3078        if excerpt_edits.is_empty() {
3079            return;
3080        }
3081
3082        let mut excerpts = snapshot.excerpts.cursor::<ExcerptOffset>(&());
3083        let mut old_diff_transforms = snapshot
3084            .diff_transforms
3085            .cursor::<(ExcerptOffset, usize)>(&());
3086        let mut new_diff_transforms = SumTree::default();
3087        let mut old_expanded_hunks = HashSet::default();
3088        let mut output_edits = Vec::new();
3089        let mut output_delta = 0_isize;
3090        let mut at_transform_boundary = true;
3091        let mut end_of_current_insert = None;
3092
3093        let mut excerpt_edits = excerpt_edits.into_iter().peekable();
3094        while let Some(edit) = excerpt_edits.next() {
3095            excerpts.seek_forward(&edit.new.start, Bias::Right, &());
3096            if excerpts.item().is_none() && *excerpts.start() == edit.new.start {
3097                excerpts.prev(&());
3098            }
3099
3100            // Keep any transforms that are before the edit.
3101            if at_transform_boundary {
3102                at_transform_boundary = false;
3103                let transforms_before_edit =
3104                    old_diff_transforms.slice(&edit.old.start, Bias::Left, &());
3105                self.append_diff_transforms(&mut new_diff_transforms, transforms_before_edit);
3106                if let Some(transform) = old_diff_transforms.item() {
3107                    if old_diff_transforms.end(&()).0 == edit.old.start
3108                        && old_diff_transforms.start().0 < edit.old.start
3109                    {
3110                        self.push_diff_transform(&mut new_diff_transforms, transform.clone());
3111                        old_diff_transforms.next(&());
3112                    }
3113                }
3114            }
3115
3116            // Compute the start of the edit in output coordinates.
3117            let edit_start_overshoot = (edit.old.start - old_diff_transforms.start().0).value;
3118            let edit_old_start = old_diff_transforms.start().1 + edit_start_overshoot;
3119            let edit_new_start = (edit_old_start as isize + output_delta) as usize;
3120
3121            let changed_diff_hunks = self.recompute_diff_transforms_for_edit(
3122                &edit,
3123                &mut excerpts,
3124                &mut old_diff_transforms,
3125                &mut new_diff_transforms,
3126                &mut end_of_current_insert,
3127                &mut old_expanded_hunks,
3128                &snapshot,
3129                change_kind,
3130            );
3131
3132            // Compute the end of the edit in output coordinates.
3133            let edit_old_end_overshoot = edit.old.end - old_diff_transforms.start().0;
3134            let edit_new_end_overshoot = edit.new.end - new_diff_transforms.summary().excerpt_len();
3135            let edit_old_end = old_diff_transforms.start().1 + edit_old_end_overshoot.value;
3136            let edit_new_end =
3137                new_diff_transforms.summary().output.len + edit_new_end_overshoot.value;
3138            let output_edit = Edit {
3139                old: edit_old_start..edit_old_end,
3140                new: edit_new_start..edit_new_end,
3141            };
3142
3143            output_delta += (output_edit.new.end - output_edit.new.start) as isize;
3144            output_delta -= (output_edit.old.end - output_edit.old.start) as isize;
3145            if changed_diff_hunks || matches!(change_kind, DiffChangeKind::BufferEdited) {
3146                output_edits.push(output_edit);
3147            }
3148
3149            // If this is the last edit that intersects the current diff transform,
3150            // then recreate the content up to the end of this transform, to prepare
3151            // for reusing additional slices of the old transforms.
3152            if excerpt_edits.peek().map_or(true, |next_edit| {
3153                next_edit.old.start >= old_diff_transforms.end(&()).0
3154            }) {
3155                let keep_next_old_transform = (old_diff_transforms.start().0 >= edit.old.end)
3156                    && match old_diff_transforms.item() {
3157                        Some(DiffTransform::BufferContent {
3158                            inserted_hunk_info: Some(hunk),
3159                            ..
3160                        }) => excerpts.item().is_some_and(|excerpt| {
3161                            hunk.hunk_start_anchor.is_valid(&excerpt.buffer)
3162                        }),
3163                        _ => true,
3164                    };
3165
3166                let mut excerpt_offset = edit.new.end;
3167                if !keep_next_old_transform {
3168                    excerpt_offset += old_diff_transforms.end(&()).0 - edit.old.end;
3169                    old_diff_transforms.next(&());
3170                }
3171
3172                old_expanded_hunks.clear();
3173                self.push_buffer_content_transform(
3174                    &snapshot,
3175                    &mut new_diff_transforms,
3176                    excerpt_offset,
3177                    end_of_current_insert,
3178                );
3179                at_transform_boundary = true;
3180            }
3181        }
3182
3183        // Keep any transforms that are after the last edit.
3184        self.append_diff_transforms(&mut new_diff_transforms, old_diff_transforms.suffix(&()));
3185
3186        // Ensure there's always at least one buffer content transform.
3187        if new_diff_transforms.is_empty() {
3188            new_diff_transforms.push(
3189                DiffTransform::BufferContent {
3190                    summary: Default::default(),
3191                    inserted_hunk_info: None,
3192                },
3193                &(),
3194            );
3195        }
3196
3197        self.subscriptions.publish(output_edits);
3198        drop(old_diff_transforms);
3199        drop(excerpts);
3200        snapshot.diff_transforms = new_diff_transforms;
3201        snapshot.edit_count += 1;
3202
3203        #[cfg(any(test, feature = "test-support"))]
3204        snapshot.check_invariants();
3205    }
3206
3207    fn recompute_diff_transforms_for_edit(
3208        &self,
3209        edit: &Edit<TypedOffset<Excerpt>>,
3210        excerpts: &mut Cursor<Excerpt, TypedOffset<Excerpt>>,
3211        old_diff_transforms: &mut Cursor<DiffTransform, (TypedOffset<Excerpt>, usize)>,
3212        new_diff_transforms: &mut SumTree<DiffTransform>,
3213        end_of_current_insert: &mut Option<(TypedOffset<Excerpt>, DiffTransformHunkInfo)>,
3214        old_expanded_hunks: &mut HashSet<DiffTransformHunkInfo>,
3215        snapshot: &MultiBufferSnapshot,
3216        change_kind: DiffChangeKind,
3217    ) -> bool {
3218        log::trace!(
3219            "recomputing diff transform for edit {:?} => {:?}",
3220            edit.old.start.value..edit.old.end.value,
3221            edit.new.start.value..edit.new.end.value
3222        );
3223
3224        // Record which hunks were previously expanded.
3225        while let Some(item) = old_diff_transforms.item() {
3226            if let Some(hunk_info) = item.hunk_info() {
3227                log::trace!(
3228                    "previously expanded hunk at {}",
3229                    old_diff_transforms.start().0
3230                );
3231                old_expanded_hunks.insert(hunk_info);
3232            }
3233            if old_diff_transforms.end(&()).0 > edit.old.end {
3234                break;
3235            }
3236            old_diff_transforms.next(&());
3237        }
3238
3239        // Avoid querying diff hunks if there's no possibility of hunks being expanded.
3240        let all_diff_hunks_expanded = snapshot.all_diff_hunks_expanded;
3241        if old_expanded_hunks.is_empty()
3242            && change_kind == DiffChangeKind::BufferEdited
3243            && !all_diff_hunks_expanded
3244        {
3245            return false;
3246        }
3247
3248        // Visit each excerpt that intersects the edit.
3249        let mut did_expand_hunks = false;
3250        while let Some(excerpt) = excerpts.item() {
3251            // Recompute the expanded hunks in the portion of the excerpt that
3252            // intersects the edit.
3253            if let Some(diff) = snapshot.diffs.get(&excerpt.buffer_id) {
3254                let buffer = &excerpt.buffer;
3255                let excerpt_start = *excerpts.start();
3256                let excerpt_end = excerpt_start + ExcerptOffset::new(excerpt.text_summary.len);
3257                let excerpt_buffer_start = excerpt.range.context.start.to_offset(buffer);
3258                let excerpt_buffer_end = excerpt_buffer_start + excerpt.text_summary.len;
3259                let edit_buffer_start =
3260                    excerpt_buffer_start + edit.new.start.value.saturating_sub(excerpt_start.value);
3261                let edit_buffer_end =
3262                    excerpt_buffer_start + edit.new.end.value.saturating_sub(excerpt_start.value);
3263                let edit_buffer_end = edit_buffer_end.min(excerpt_buffer_end);
3264                let edit_anchor_range =
3265                    buffer.anchor_before(edit_buffer_start)..buffer.anchor_after(edit_buffer_end);
3266
3267                for hunk in diff.hunks_intersecting_range(edit_anchor_range, buffer) {
3268                    if hunk.is_created_file() && !all_diff_hunks_expanded {
3269                        continue;
3270                    }
3271
3272                    let hunk_buffer_range = hunk.buffer_range.to_offset(buffer);
3273                    if hunk_buffer_range.start < excerpt_buffer_start {
3274                        log::trace!("skipping hunk that starts before excerpt");
3275                        continue;
3276                    }
3277
3278                    let hunk_info = DiffTransformHunkInfo {
3279                        excerpt_id: excerpt.id,
3280                        hunk_start_anchor: hunk.buffer_range.start,
3281                        hunk_secondary_status: hunk.secondary_status,
3282                    };
3283
3284                    let hunk_excerpt_start = excerpt_start
3285                        + ExcerptOffset::new(
3286                            hunk_buffer_range.start.saturating_sub(excerpt_buffer_start),
3287                        );
3288                    let hunk_excerpt_end = excerpt_end.min(
3289                        excerpt_start
3290                            + ExcerptOffset::new(hunk_buffer_range.end - excerpt_buffer_start),
3291                    );
3292
3293                    self.push_buffer_content_transform(
3294                        snapshot,
3295                        new_diff_transforms,
3296                        hunk_excerpt_start,
3297                        *end_of_current_insert,
3298                    );
3299
3300                    // For every existing hunk, determine if it was previously expanded
3301                    // and if it should currently be expanded.
3302                    let was_previously_expanded = old_expanded_hunks.contains(&hunk_info);
3303                    let should_expand_hunk = match &change_kind {
3304                        DiffChangeKind::DiffUpdated { base_changed: true } => {
3305                            was_previously_expanded || all_diff_hunks_expanded
3306                        }
3307                        DiffChangeKind::ExpandOrCollapseHunks { expand } => {
3308                            let intersects = hunk_buffer_range.is_empty()
3309                                || hunk_buffer_range.end > edit_buffer_start;
3310                            if *expand {
3311                                intersects || was_previously_expanded || all_diff_hunks_expanded
3312                            } else {
3313                                !intersects && (was_previously_expanded || all_diff_hunks_expanded)
3314                            }
3315                        }
3316                        _ => was_previously_expanded || all_diff_hunks_expanded,
3317                    };
3318
3319                    if should_expand_hunk {
3320                        did_expand_hunks = true;
3321                        log::trace!(
3322                            "expanding hunk {:?}, excerpt:{:?}",
3323                            hunk_excerpt_start.value..hunk_excerpt_end.value,
3324                            excerpt.id
3325                        );
3326
3327                        if !hunk.diff_base_byte_range.is_empty()
3328                            && hunk_buffer_range.start >= edit_buffer_start
3329                            && hunk_buffer_range.start <= excerpt_buffer_end
3330                        {
3331                            let base_text = diff.base_text();
3332                            let mut text_cursor =
3333                                base_text.as_rope().cursor(hunk.diff_base_byte_range.start);
3334                            let mut base_text_summary =
3335                                text_cursor.summary::<TextSummary>(hunk.diff_base_byte_range.end);
3336
3337                            let mut has_trailing_newline = false;
3338                            if base_text_summary.last_line_chars > 0 {
3339                                base_text_summary += TextSummary::newline();
3340                                has_trailing_newline = true;
3341                            }
3342
3343                            new_diff_transforms.push(
3344                                DiffTransform::DeletedHunk {
3345                                    base_text_byte_range: hunk.diff_base_byte_range.clone(),
3346                                    summary: base_text_summary,
3347                                    buffer_id: excerpt.buffer_id,
3348                                    hunk_info,
3349                                    has_trailing_newline,
3350                                },
3351                                &(),
3352                            );
3353                        }
3354
3355                        if !hunk_buffer_range.is_empty() {
3356                            *end_of_current_insert =
3357                                Some((hunk_excerpt_end.min(excerpt_end), hunk_info));
3358                        }
3359                    }
3360                }
3361            }
3362
3363            if excerpts.end(&()) <= edit.new.end {
3364                excerpts.next(&());
3365            } else {
3366                break;
3367            }
3368        }
3369
3370        did_expand_hunks || !old_expanded_hunks.is_empty()
3371    }
3372
3373    fn append_diff_transforms(
3374        &self,
3375        new_transforms: &mut SumTree<DiffTransform>,
3376        subtree: SumTree<DiffTransform>,
3377    ) {
3378        if let Some(DiffTransform::BufferContent {
3379            inserted_hunk_info,
3380            summary,
3381        }) = subtree.first()
3382        {
3383            if self.extend_last_buffer_content_transform(
3384                new_transforms,
3385                *inserted_hunk_info,
3386                *summary,
3387            ) {
3388                let mut cursor = subtree.cursor::<()>(&());
3389                cursor.next(&());
3390                cursor.next(&());
3391                new_transforms.append(cursor.suffix(&()), &());
3392                return;
3393            }
3394        }
3395        new_transforms.append(subtree, &());
3396    }
3397
3398    fn push_diff_transform(
3399        &self,
3400        new_transforms: &mut SumTree<DiffTransform>,
3401        transform: DiffTransform,
3402    ) {
3403        if let DiffTransform::BufferContent {
3404            inserted_hunk_info: inserted_hunk_anchor,
3405            summary,
3406        } = transform
3407        {
3408            if self.extend_last_buffer_content_transform(
3409                new_transforms,
3410                inserted_hunk_anchor,
3411                summary,
3412            ) {
3413                return;
3414            }
3415        }
3416        new_transforms.push(transform, &());
3417    }
3418
3419    fn push_buffer_content_transform(
3420        &self,
3421        old_snapshot: &MultiBufferSnapshot,
3422        new_transforms: &mut SumTree<DiffTransform>,
3423        end_offset: ExcerptOffset,
3424        current_inserted_hunk: Option<(ExcerptOffset, DiffTransformHunkInfo)>,
3425    ) {
3426        let inserted_region = current_inserted_hunk.map(|(insertion_end_offset, hunk_info)| {
3427            (end_offset.min(insertion_end_offset), Some(hunk_info))
3428        });
3429        let unchanged_region = [(end_offset, None)];
3430
3431        for (end_offset, inserted_hunk_info) in inserted_region.into_iter().chain(unchanged_region)
3432        {
3433            let start_offset = new_transforms.summary().excerpt_len();
3434            if end_offset <= start_offset {
3435                continue;
3436            }
3437            let summary_to_add = old_snapshot
3438                .text_summary_for_excerpt_offset_range::<TextSummary>(start_offset..end_offset);
3439
3440            if !self.extend_last_buffer_content_transform(
3441                new_transforms,
3442                inserted_hunk_info,
3443                summary_to_add,
3444            ) {
3445                new_transforms.push(
3446                    DiffTransform::BufferContent {
3447                        summary: summary_to_add,
3448                        inserted_hunk_info,
3449                    },
3450                    &(),
3451                )
3452            }
3453        }
3454    }
3455
3456    fn extend_last_buffer_content_transform(
3457        &self,
3458        new_transforms: &mut SumTree<DiffTransform>,
3459        new_inserted_hunk_info: Option<DiffTransformHunkInfo>,
3460        summary_to_add: TextSummary,
3461    ) -> bool {
3462        let mut did_extend = false;
3463        new_transforms.update_last(
3464            |last_transform| {
3465                if let DiffTransform::BufferContent {
3466                    summary,
3467                    inserted_hunk_info: inserted_hunk_anchor,
3468                } = last_transform
3469                {
3470                    if *inserted_hunk_anchor == new_inserted_hunk_info {
3471                        *summary += summary_to_add;
3472                        did_extend = true;
3473                    }
3474                }
3475            },
3476            &(),
3477        );
3478        did_extend
3479    }
3480}
3481
3482#[cfg(any(test, feature = "test-support"))]
3483impl MultiBuffer {
3484    pub fn build_simple(text: &str, cx: &mut gpui::App) -> Entity<Self> {
3485        let buffer = cx.new(|cx| Buffer::local(text, cx));
3486        cx.new(|cx| Self::singleton(buffer, cx))
3487    }
3488
3489    pub fn build_multi<const COUNT: usize>(
3490        excerpts: [(&str, Vec<Range<Point>>); COUNT],
3491        cx: &mut gpui::App,
3492    ) -> Entity<Self> {
3493        let multi = cx.new(|_| Self::new(Capability::ReadWrite));
3494        for (text, ranges) in excerpts {
3495            let buffer = cx.new(|cx| Buffer::local(text, cx));
3496            let excerpt_ranges = ranges
3497                .into_iter()
3498                .map(|range| ExcerptRange::new(range.clone()));
3499            multi.update(cx, |multi, cx| {
3500                multi.push_excerpts(buffer, excerpt_ranges, cx)
3501            });
3502        }
3503
3504        multi
3505    }
3506
3507    pub fn build_from_buffer(buffer: Entity<Buffer>, cx: &mut gpui::App) -> Entity<Self> {
3508        cx.new(|cx| Self::singleton(buffer, cx))
3509    }
3510
3511    pub fn build_random(rng: &mut impl rand::Rng, cx: &mut gpui::App) -> Entity<Self> {
3512        cx.new(|cx| {
3513            let mut multibuffer = MultiBuffer::new(Capability::ReadWrite);
3514            let mutation_count = rng.gen_range(1..=5);
3515            multibuffer.randomly_edit_excerpts(rng, mutation_count, cx);
3516            multibuffer
3517        })
3518    }
3519
3520    pub fn randomly_edit(
3521        &mut self,
3522        rng: &mut impl rand::Rng,
3523        edit_count: usize,
3524        cx: &mut Context<Self>,
3525    ) {
3526        use util::RandomCharIter;
3527
3528        let snapshot = self.read(cx);
3529        let mut edits: Vec<(Range<usize>, Arc<str>)> = Vec::new();
3530        let mut last_end = None;
3531        for _ in 0..edit_count {
3532            if last_end.map_or(false, |last_end| last_end >= snapshot.len()) {
3533                break;
3534            }
3535
3536            let new_start = last_end.map_or(0, |last_end| last_end + 1);
3537            let end = snapshot.clip_offset(rng.gen_range(new_start..=snapshot.len()), Bias::Right);
3538            let start = snapshot.clip_offset(rng.gen_range(new_start..=end), Bias::Right);
3539            last_end = Some(end);
3540
3541            let mut range = start..end;
3542            if rng.gen_bool(0.2) {
3543                mem::swap(&mut range.start, &mut range.end);
3544            }
3545
3546            let new_text_len = rng.gen_range(0..10);
3547            let new_text: String = RandomCharIter::new(&mut *rng).take(new_text_len).collect();
3548
3549            edits.push((range, new_text.into()));
3550        }
3551        log::info!("mutating multi-buffer with {:?}", edits);
3552        drop(snapshot);
3553
3554        self.edit(edits, None, cx);
3555    }
3556
3557    pub fn randomly_edit_excerpts(
3558        &mut self,
3559        rng: &mut impl rand::Rng,
3560        mutation_count: usize,
3561        cx: &mut Context<Self>,
3562    ) {
3563        use rand::prelude::*;
3564        use std::env;
3565        use util::RandomCharIter;
3566
3567        let max_excerpts = env::var("MAX_EXCERPTS")
3568            .map(|i| i.parse().expect("invalid `MAX_EXCERPTS` variable"))
3569            .unwrap_or(5);
3570
3571        let mut buffers = Vec::new();
3572        for _ in 0..mutation_count {
3573            if rng.gen_bool(0.05) {
3574                log::info!("Clearing multi-buffer");
3575                self.clear(cx);
3576                continue;
3577            } else if rng.gen_bool(0.1) && !self.excerpt_ids().is_empty() {
3578                let ids = self.excerpt_ids();
3579                let mut excerpts = HashSet::default();
3580                for _ in 0..rng.gen_range(0..ids.len()) {
3581                    excerpts.extend(ids.choose(rng).copied());
3582                }
3583
3584                let line_count = rng.gen_range(0..5);
3585
3586                log::info!("Expanding excerpts {excerpts:?} by {line_count} lines");
3587
3588                self.expand_excerpts(
3589                    excerpts.iter().cloned(),
3590                    line_count,
3591                    ExpandExcerptDirection::UpAndDown,
3592                    cx,
3593                );
3594                continue;
3595            }
3596
3597            let excerpt_ids = self.excerpt_ids();
3598            if excerpt_ids.is_empty() || (rng.r#gen() && excerpt_ids.len() < max_excerpts) {
3599                let buffer_handle = if rng.r#gen() || self.buffers.borrow().is_empty() {
3600                    let text = RandomCharIter::new(&mut *rng).take(10).collect::<String>();
3601                    buffers.push(cx.new(|cx| Buffer::local(text, cx)));
3602                    let buffer = buffers.last().unwrap().read(cx);
3603                    log::info!(
3604                        "Creating new buffer {} with text: {:?}",
3605                        buffer.remote_id(),
3606                        buffer.text()
3607                    );
3608                    buffers.last().unwrap().clone()
3609                } else {
3610                    self.buffers
3611                        .borrow()
3612                        .values()
3613                        .choose(rng)
3614                        .unwrap()
3615                        .buffer
3616                        .clone()
3617                };
3618
3619                let buffer = buffer_handle.read(cx);
3620                let buffer_text = buffer.text();
3621                let ranges = (0..rng.gen_range(0..5))
3622                    .map(|_| {
3623                        let end_ix =
3624                            buffer.clip_offset(rng.gen_range(0..=buffer.len()), Bias::Right);
3625                        let start_ix = buffer.clip_offset(rng.gen_range(0..=end_ix), Bias::Left);
3626                        ExcerptRange::new(start_ix..end_ix)
3627                    })
3628                    .collect::<Vec<_>>();
3629                log::info!(
3630                    "Inserting excerpts from buffer {} and ranges {:?}: {:?}",
3631                    buffer_handle.read(cx).remote_id(),
3632                    ranges.iter().map(|r| &r.context).collect::<Vec<_>>(),
3633                    ranges
3634                        .iter()
3635                        .map(|r| &buffer_text[r.context.clone()])
3636                        .collect::<Vec<_>>()
3637                );
3638
3639                let excerpt_id = self.push_excerpts(buffer_handle.clone(), ranges, cx);
3640                log::info!("Inserted with ids: {:?}", excerpt_id);
3641            } else {
3642                let remove_count = rng.gen_range(1..=excerpt_ids.len());
3643                let mut excerpts_to_remove = excerpt_ids
3644                    .choose_multiple(rng, remove_count)
3645                    .cloned()
3646                    .collect::<Vec<_>>();
3647                let snapshot = self.snapshot.borrow();
3648                excerpts_to_remove.sort_unstable_by(|a, b| a.cmp(b, &snapshot));
3649                drop(snapshot);
3650                log::info!("Removing excerpts {:?}", excerpts_to_remove);
3651                self.remove_excerpts(excerpts_to_remove, cx);
3652            }
3653        }
3654    }
3655
3656    pub fn randomly_mutate(
3657        &mut self,
3658        rng: &mut impl rand::Rng,
3659        mutation_count: usize,
3660        cx: &mut Context<Self>,
3661    ) {
3662        use rand::prelude::*;
3663
3664        if rng.gen_bool(0.7) || self.singleton {
3665            let buffer = self
3666                .buffers
3667                .borrow()
3668                .values()
3669                .choose(rng)
3670                .map(|state| state.buffer.clone());
3671
3672            if let Some(buffer) = buffer {
3673                buffer.update(cx, |buffer, cx| {
3674                    if rng.r#gen() {
3675                        buffer.randomly_edit(rng, mutation_count, cx);
3676                    } else {
3677                        buffer.randomly_undo_redo(rng, cx);
3678                    }
3679                });
3680            } else {
3681                self.randomly_edit(rng, mutation_count, cx);
3682            }
3683        } else {
3684            self.randomly_edit_excerpts(rng, mutation_count, cx);
3685        }
3686
3687        self.check_invariants(cx);
3688    }
3689
3690    fn check_invariants(&self, cx: &App) {
3691        self.read(cx).check_invariants();
3692    }
3693}
3694
3695impl EventEmitter<Event> for MultiBuffer {}
3696
3697impl MultiBufferSnapshot {
3698    pub fn text(&self) -> String {
3699        self.chunks(0..self.len(), false)
3700            .map(|chunk| chunk.text)
3701            .collect()
3702    }
3703
3704    pub fn reversed_chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3705        self.reversed_chunks_in_range(0..position.to_offset(self))
3706            .flat_map(|c| c.chars().rev())
3707    }
3708
3709    fn reversed_chunks_in_range(&self, range: Range<usize>) -> ReversedMultiBufferChunks {
3710        let mut cursor = self.cursor::<usize>();
3711        cursor.seek(&range.end);
3712        let current_chunks = cursor.region().as_ref().map(|region| {
3713            let start_overshoot = range.start.saturating_sub(region.range.start);
3714            let end_overshoot = range.end - region.range.start;
3715            let end = (region.buffer_range.start + end_overshoot).min(region.buffer_range.end);
3716            let start = region.buffer_range.start + start_overshoot;
3717            region.buffer.reversed_chunks_in_range(start..end)
3718        });
3719        ReversedMultiBufferChunks {
3720            cursor,
3721            current_chunks,
3722            start: range.start,
3723            offset: range.end,
3724        }
3725    }
3726
3727    pub fn chars_at<T: ToOffset>(&self, position: T) -> impl Iterator<Item = char> + '_ {
3728        let offset = position.to_offset(self);
3729        self.text_for_range(offset..self.len())
3730            .flat_map(|chunk| chunk.chars())
3731    }
3732
3733    pub fn text_for_range<T: ToOffset>(&self, range: Range<T>) -> impl Iterator<Item = &str> + '_ {
3734        self.chunks(range, false).map(|chunk| chunk.text)
3735    }
3736
3737    pub fn is_line_blank(&self, row: MultiBufferRow) -> bool {
3738        self.text_for_range(Point::new(row.0, 0)..Point::new(row.0, self.line_len(row)))
3739            .all(|chunk| chunk.matches(|c: char| !c.is_whitespace()).next().is_none())
3740    }
3741
3742    pub fn contains_str_at<T>(&self, position: T, needle: &str) -> bool
3743    where
3744        T: ToOffset,
3745    {
3746        let position = position.to_offset(self);
3747        position == self.clip_offset(position, Bias::Left)
3748            && self
3749                .bytes_in_range(position..self.len())
3750                .flatten()
3751                .copied()
3752                .take(needle.len())
3753                .eq(needle.bytes())
3754    }
3755
3756    pub fn diff_hunks(&self) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3757        self.diff_hunks_in_range(Anchor::min()..Anchor::max())
3758    }
3759
3760    pub fn diff_hunks_in_range<T: ToPoint>(
3761        &self,
3762        range: Range<T>,
3763    ) -> impl Iterator<Item = MultiBufferDiffHunk> + '_ {
3764        let query_range = range.start.to_point(self)..range.end.to_point(self);
3765        self.lift_buffer_metadata(query_range.clone(), move |buffer, buffer_range| {
3766            let diff = self.diffs.get(&buffer.remote_id())?;
3767            let buffer_start = buffer.anchor_before(buffer_range.start);
3768            let buffer_end = buffer.anchor_after(buffer_range.end);
3769            Some(
3770                diff.hunks_intersecting_range(buffer_start..buffer_end, buffer)
3771                    .filter_map(|hunk| {
3772                        if hunk.is_created_file() && !self.all_diff_hunks_expanded {
3773                            return None;
3774                        }
3775                        Some((hunk.range.clone(), hunk))
3776                    }),
3777            )
3778        })
3779        .filter_map(move |(range, hunk, excerpt)| {
3780            if range.start != range.end && range.end == query_range.start && !hunk.range.is_empty()
3781            {
3782                return None;
3783            }
3784            let end_row = if range.end.column == 0 {
3785                range.end.row
3786            } else {
3787                range.end.row + 1
3788            };
3789            Some(MultiBufferDiffHunk {
3790                row_range: MultiBufferRow(range.start.row)..MultiBufferRow(end_row),
3791                buffer_id: excerpt.buffer_id,
3792                excerpt_id: excerpt.id,
3793                buffer_range: hunk.buffer_range.clone(),
3794                diff_base_byte_range: hunk.diff_base_byte_range.clone(),
3795                secondary_status: hunk.secondary_status,
3796            })
3797        })
3798    }
3799
3800    pub fn excerpt_ids_for_range<T: ToOffset>(
3801        &self,
3802        range: Range<T>,
3803    ) -> impl Iterator<Item = ExcerptId> + '_ {
3804        let range = range.start.to_offset(self)..range.end.to_offset(self);
3805        let mut cursor = self.cursor::<usize>();
3806        cursor.seek(&range.start);
3807        std::iter::from_fn(move || {
3808            let region = cursor.region()?;
3809            if region.range.start >= range.end {
3810                return None;
3811            }
3812            cursor.next_excerpt();
3813            Some(region.excerpt.id)
3814        })
3815    }
3816
3817    pub fn buffer_ids_for_range<T: ToOffset>(
3818        &self,
3819        range: Range<T>,
3820    ) -> impl Iterator<Item = BufferId> + '_ {
3821        let range = range.start.to_offset(self)..range.end.to_offset(self);
3822        let mut cursor = self.cursor::<usize>();
3823        cursor.seek(&range.start);
3824        std::iter::from_fn(move || {
3825            let region = cursor.region()?;
3826            if region.range.start > range.end
3827                || region.range.start == range.end && region.range.start > range.start
3828            {
3829                return None;
3830            }
3831            cursor.next_excerpt();
3832            Some(region.excerpt.buffer_id)
3833        })
3834    }
3835
3836    pub fn ranges_to_buffer_ranges<T: ToOffset>(
3837        &self,
3838        ranges: impl Iterator<Item = Range<T>>,
3839    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId)> {
3840        ranges.flat_map(|range| self.range_to_buffer_ranges(range).into_iter())
3841    }
3842
3843    pub fn range_to_buffer_ranges<T: ToOffset>(
3844        &self,
3845        range: Range<T>,
3846    ) -> Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> {
3847        let start = range.start.to_offset(&self);
3848        let end = range.end.to_offset(&self);
3849
3850        let mut cursor = self.cursor::<usize>();
3851        cursor.seek(&start);
3852
3853        let mut result: Vec<(&BufferSnapshot, Range<usize>, ExcerptId)> = Vec::new();
3854        while let Some(region) = cursor.region() {
3855            if region.range.start > end {
3856                break;
3857            }
3858            if region.is_main_buffer {
3859                let start_overshoot = start.saturating_sub(region.range.start);
3860                let end_overshoot = end.saturating_sub(region.range.start);
3861                let start = region
3862                    .buffer_range
3863                    .end
3864                    .min(region.buffer_range.start + start_overshoot);
3865                let end = region
3866                    .buffer_range
3867                    .end
3868                    .min(region.buffer_range.start + end_overshoot);
3869                if let Some(prev) = result.last_mut().filter(|(_, prev_range, excerpt_id)| {
3870                    *excerpt_id == region.excerpt.id && prev_range.end == start
3871                }) {
3872                    prev.1.end = end;
3873                } else {
3874                    result.push((region.buffer, start..end, region.excerpt.id));
3875                }
3876            }
3877            cursor.next();
3878        }
3879        result
3880    }
3881
3882    pub fn range_to_buffer_ranges_with_deleted_hunks<T: ToOffset>(
3883        &self,
3884        range: Range<T>,
3885    ) -> impl Iterator<Item = (&BufferSnapshot, Range<usize>, ExcerptId, Option<Anchor>)> + '_ {
3886        let start = range.start.to_offset(&self);
3887        let end = range.end.to_offset(&self);
3888
3889        let mut cursor = self.cursor::<usize>();
3890        cursor.seek(&start);
3891
3892        std::iter::from_fn(move || {
3893            let region = cursor.region()?;
3894            if region.range.start > end {
3895                return None;
3896            }
3897            let start_overshoot = start.saturating_sub(region.range.start);
3898            let end_overshoot = end.saturating_sub(region.range.start);
3899            let start = region
3900                .buffer_range
3901                .end
3902                .min(region.buffer_range.start + start_overshoot);
3903            let end = region
3904                .buffer_range
3905                .end
3906                .min(region.buffer_range.start + end_overshoot);
3907
3908            let region_excerpt_id = region.excerpt.id;
3909            let deleted_hunk_anchor = if region.is_main_buffer {
3910                None
3911            } else {
3912                Some(self.anchor_before(region.range.start))
3913            };
3914            let result = (
3915                region.buffer,
3916                start..end,
3917                region_excerpt_id,
3918                deleted_hunk_anchor,
3919            );
3920            cursor.next();
3921            Some(result)
3922        })
3923    }
3924
3925    /// Retrieves buffer metadata for the given range, and converts it into multi-buffer
3926    /// coordinates.
3927    ///
3928    /// The given callback will be called for every excerpt intersecting the given range. It will
3929    /// be passed the excerpt's buffer and the buffer range that the input range intersects.
3930    /// The callback should return an iterator of metadata items from that buffer, each paired
3931    /// with a buffer range.
3932    ///
3933    /// The returned iterator yields each of these metadata items, paired with its range in
3934    /// multi-buffer coordinates.
3935    fn lift_buffer_metadata<'a, D, M, I>(
3936        &'a self,
3937        query_range: Range<D>,
3938        get_buffer_metadata: impl 'a + Fn(&'a BufferSnapshot, Range<D>) -> Option<I>,
3939    ) -> impl Iterator<Item = (Range<D>, M, &'a Excerpt)> + 'a
3940    where
3941        I: Iterator<Item = (Range<D>, M)> + 'a,
3942        D: TextDimension + Ord + Sub<D, Output = D>,
3943    {
3944        let max_position = D::from_text_summary(&self.text_summary());
3945        let mut current_excerpt_metadata: Option<(ExcerptId, I)> = None;
3946        let mut cursor = self.cursor::<D>();
3947
3948        // Find the excerpt and buffer offset where the given range ends.
3949        cursor.seek(&query_range.end);
3950        let mut range_end = None;
3951        while let Some(region) = cursor.region() {
3952            if region.is_main_buffer {
3953                let mut buffer_end = region.buffer_range.start;
3954                let overshoot = if query_range.end > region.range.start {
3955                    query_range.end - region.range.start
3956                } else {
3957                    D::default()
3958                };
3959                buffer_end.add_assign(&overshoot);
3960                range_end = Some((region.excerpt.id, buffer_end));
3961                break;
3962            }
3963            cursor.next();
3964        }
3965
3966        cursor.seek(&query_range.start);
3967
3968        if let Some(region) = cursor.region().filter(|region| !region.is_main_buffer) {
3969            if region.range.start > D::zero(&()) {
3970                cursor.prev()
3971            }
3972        }
3973
3974        iter::from_fn(move || {
3975            loop {
3976                let excerpt = cursor.excerpt()?;
3977
3978                // If we have already retrieved metadata for this excerpt, continue to use it.
3979                let metadata_iter = if let Some((_, metadata)) = current_excerpt_metadata
3980                    .as_mut()
3981                    .filter(|(excerpt_id, _)| *excerpt_id == excerpt.id)
3982                {
3983                    Some(metadata)
3984                }
3985                // Otherwise, compute the intersection of the input range with the excerpt's range,
3986                // and retrieve the metadata for the resulting range.
3987                else {
3988                    let region = cursor.region()?;
3989                    let mut buffer_start;
3990                    if region.is_main_buffer {
3991                        buffer_start = region.buffer_range.start;
3992                        if query_range.start > region.range.start {
3993                            let overshoot = query_range.start - region.range.start;
3994                            buffer_start.add_assign(&overshoot);
3995                        }
3996                        buffer_start = buffer_start.min(region.buffer_range.end);
3997                    } else {
3998                        buffer_start = cursor.main_buffer_position()?;
3999                    };
4000                    let mut buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4001                    if let Some((end_excerpt_id, end_buffer_offset)) = range_end {
4002                        if excerpt.id == end_excerpt_id {
4003                            buffer_end = buffer_end.min(end_buffer_offset);
4004                        }
4005                    }
4006
4007                    if let Some(iterator) =
4008                        get_buffer_metadata(&excerpt.buffer, buffer_start..buffer_end)
4009                    {
4010                        Some(&mut current_excerpt_metadata.insert((excerpt.id, iterator)).1)
4011                    } else {
4012                        None
4013                    }
4014                };
4015
4016                // Visit each metadata item.
4017                if let Some((metadata_buffer_range, metadata)) =
4018                    metadata_iter.and_then(Iterator::next)
4019                {
4020                    // Find the multibuffer regions that contain the start and end of
4021                    // the metadata item's range.
4022                    if metadata_buffer_range.start > D::default() {
4023                        while let Some(region) = cursor.region() {
4024                            if region.is_main_buffer
4025                                && (region.buffer_range.end >= metadata_buffer_range.start
4026                                    || cursor.is_at_end_of_excerpt())
4027                            {
4028                                break;
4029                            }
4030                            cursor.next();
4031                        }
4032                    }
4033                    let start_region = cursor.region()?;
4034                    while let Some(region) = cursor.region() {
4035                        if region.is_main_buffer
4036                            && (region.buffer_range.end > metadata_buffer_range.end
4037                                || cursor.is_at_end_of_excerpt())
4038                        {
4039                            break;
4040                        }
4041                        cursor.next();
4042                    }
4043                    let end_region = cursor.region();
4044
4045                    // Convert the metadata item's range into multibuffer coordinates.
4046                    let mut start_position = start_region.range.start;
4047                    let region_buffer_start = start_region.buffer_range.start;
4048                    if start_region.is_main_buffer
4049                        && metadata_buffer_range.start > region_buffer_start
4050                    {
4051                        start_position
4052                            .add_assign(&(metadata_buffer_range.start - region_buffer_start));
4053                        start_position = start_position.min(start_region.range.end);
4054                    }
4055
4056                    let mut end_position = max_position;
4057                    if let Some(end_region) = &end_region {
4058                        end_position = end_region.range.start;
4059                        debug_assert!(end_region.is_main_buffer);
4060                        let region_buffer_start = end_region.buffer_range.start;
4061                        if metadata_buffer_range.end > region_buffer_start {
4062                            end_position
4063                                .add_assign(&(metadata_buffer_range.end - region_buffer_start));
4064                        }
4065                        end_position = end_position.min(end_region.range.end);
4066                    }
4067
4068                    if start_position <= query_range.end && end_position >= query_range.start {
4069                        return Some((start_position..end_position, metadata, excerpt));
4070                    }
4071                }
4072                // When there are no more metadata items for this excerpt, move to the next excerpt.
4073                else {
4074                    current_excerpt_metadata.take();
4075                    if let Some((end_excerpt_id, _)) = range_end {
4076                        if excerpt.id == end_excerpt_id {
4077                            return None;
4078                        }
4079                    }
4080                    cursor.next_excerpt();
4081                }
4082            }
4083        })
4084    }
4085
4086    pub fn diff_hunk_before<T: ToOffset>(&self, position: T) -> Option<MultiBufferRow> {
4087        let offset = position.to_offset(self);
4088
4089        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
4090        cursor.seek(&DimensionPair {
4091            key: offset,
4092            value: None,
4093        });
4094        cursor.seek_to_start_of_current_excerpt();
4095        let excerpt = cursor.excerpt()?;
4096
4097        let excerpt_end = excerpt.range.context.end.to_offset(&excerpt.buffer);
4098        let current_position = self
4099            .anchor_before(offset)
4100            .text_anchor
4101            .to_offset(&excerpt.buffer);
4102        let excerpt_end = excerpt
4103            .buffer
4104            .anchor_before(excerpt_end.min(current_position));
4105
4106        if let Some(diff) = self.diffs.get(&excerpt.buffer_id) {
4107            for hunk in diff.hunks_intersecting_range_rev(
4108                excerpt.range.context.start..excerpt_end,
4109                &excerpt.buffer,
4110            ) {
4111                let hunk_end = hunk.buffer_range.end.to_offset(&excerpt.buffer);
4112                if hunk_end >= current_position {
4113                    continue;
4114                }
4115                let start =
4116                    Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4117                        .to_point(&self);
4118                return Some(MultiBufferRow(start.row));
4119            }
4120        }
4121
4122        loop {
4123            cursor.prev_excerpt();
4124            let excerpt = cursor.excerpt()?;
4125
4126            let Some(diff) = self.diffs.get(&excerpt.buffer_id) else {
4127                continue;
4128            };
4129            let mut hunks =
4130                diff.hunks_intersecting_range_rev(excerpt.range.context.clone(), &excerpt.buffer);
4131            let Some(hunk) = hunks.next() else {
4132                continue;
4133            };
4134            let start = Anchor::in_buffer(excerpt.id, excerpt.buffer_id, hunk.buffer_range.start)
4135                .to_point(&self);
4136            return Some(MultiBufferRow(start.row));
4137        }
4138    }
4139
4140    pub fn has_diff_hunks(&self) -> bool {
4141        self.diffs.values().any(|diff| !diff.is_empty())
4142    }
4143
4144    pub fn surrounding_word<T: ToOffset>(
4145        &self,
4146        start: T,
4147        for_completion: bool,
4148    ) -> (Range<usize>, Option<CharKind>) {
4149        let mut start = start.to_offset(self);
4150        let mut end = start;
4151        let mut next_chars = self.chars_at(start).peekable();
4152        let mut prev_chars = self.reversed_chars_at(start).peekable();
4153
4154        let classifier = self
4155            .char_classifier_at(start)
4156            .for_completion(for_completion);
4157
4158        let word_kind = cmp::max(
4159            prev_chars.peek().copied().map(|c| classifier.kind(c)),
4160            next_chars.peek().copied().map(|c| classifier.kind(c)),
4161        );
4162
4163        for ch in prev_chars {
4164            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4165                start -= ch.len_utf8();
4166            } else {
4167                break;
4168            }
4169        }
4170
4171        for ch in next_chars {
4172            if Some(classifier.kind(ch)) == word_kind && ch != '\n' {
4173                end += ch.len_utf8();
4174            } else {
4175                break;
4176            }
4177        }
4178
4179        (start..end, word_kind)
4180    }
4181
4182    pub fn is_singleton(&self) -> bool {
4183        self.singleton
4184    }
4185
4186    pub fn as_singleton(&self) -> Option<(&ExcerptId, BufferId, &BufferSnapshot)> {
4187        if self.singleton {
4188            self.excerpts
4189                .iter()
4190                .next()
4191                .map(|e| (&e.id, e.buffer_id, &e.buffer))
4192        } else {
4193            None
4194        }
4195    }
4196
4197    pub fn len(&self) -> usize {
4198        self.diff_transforms.summary().output.len
4199    }
4200
4201    pub fn is_empty(&self) -> bool {
4202        self.excerpts.summary().text.len == 0
4203    }
4204
4205    pub fn widest_line_number(&self) -> u32 {
4206        // widest_line_number is 0-based, so 1 is added to get the displayed line number.
4207        self.excerpts.summary().widest_line_number + 1
4208    }
4209
4210    pub fn bytes_in_range<T: ToOffset>(&self, range: Range<T>) -> MultiBufferBytes {
4211        let range = range.start.to_offset(self)..range.end.to_offset(self);
4212        let mut excerpts = self.cursor::<usize>();
4213        excerpts.seek(&range.start);
4214
4215        let mut chunk;
4216        let mut has_trailing_newline;
4217        let excerpt_bytes;
4218        if let Some(region) = excerpts.region() {
4219            let mut bytes = region.buffer.bytes_in_range(
4220                region.buffer_range.start + range.start - region.range.start
4221                    ..(region.buffer_range.start + range.end - region.range.start)
4222                        .min(region.buffer_range.end),
4223            );
4224            chunk = bytes.next().unwrap_or(&[][..]);
4225            excerpt_bytes = Some(bytes);
4226            has_trailing_newline = region.has_trailing_newline && range.end >= region.range.end;
4227            if chunk.is_empty() && has_trailing_newline {
4228                chunk = b"\n";
4229                has_trailing_newline = false;
4230            }
4231        } else {
4232            chunk = &[][..];
4233            excerpt_bytes = None;
4234            has_trailing_newline = false;
4235        };
4236
4237        MultiBufferBytes {
4238            range,
4239            cursor: excerpts,
4240            excerpt_bytes,
4241            has_trailing_newline,
4242            chunk,
4243        }
4244    }
4245
4246    pub fn reversed_bytes_in_range<T: ToOffset>(
4247        &self,
4248        range: Range<T>,
4249    ) -> ReversedMultiBufferBytes {
4250        let range = range.start.to_offset(self)..range.end.to_offset(self);
4251        let mut chunks = self.reversed_chunks_in_range(range.clone());
4252        let chunk = chunks.next().map_or(&[][..], |c| c.as_bytes());
4253        ReversedMultiBufferBytes {
4254            range,
4255            chunks,
4256            chunk,
4257        }
4258    }
4259
4260    pub fn row_infos(&self, start_row: MultiBufferRow) -> MultiBufferRows {
4261        let mut cursor = self.cursor::<Point>();
4262        cursor.seek(&Point::new(start_row.0, 0));
4263        let mut result = MultiBufferRows {
4264            point: Point::new(0, 0),
4265            is_empty: self.excerpts.is_empty(),
4266            is_singleton: self.is_singleton(),
4267            cursor,
4268        };
4269        result.seek(start_row);
4270        result
4271    }
4272
4273    pub fn chunks<T: ToOffset>(&self, range: Range<T>, language_aware: bool) -> MultiBufferChunks {
4274        let mut chunks = MultiBufferChunks {
4275            excerpt_offset_range: ExcerptOffset::new(0)..ExcerptOffset::new(0),
4276            range: 0..0,
4277            excerpts: self.excerpts.cursor(&()),
4278            diff_transforms: self.diff_transforms.cursor(&()),
4279            diffs: &self.diffs,
4280            diff_base_chunks: None,
4281            excerpt_chunks: None,
4282            buffer_chunk: None,
4283            language_aware,
4284        };
4285        let range = range.start.to_offset(self)..range.end.to_offset(self);
4286        chunks.seek(range);
4287        chunks
4288    }
4289
4290    pub fn clip_offset(&self, offset: usize, bias: Bias) -> usize {
4291        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset)
4292    }
4293
4294    pub fn clip_point(&self, point: Point, bias: Bias) -> Point {
4295        self.clip_dimension(point, bias, text::BufferSnapshot::clip_point)
4296    }
4297
4298    pub fn clip_offset_utf16(&self, offset: OffsetUtf16, bias: Bias) -> OffsetUtf16 {
4299        self.clip_dimension(offset, bias, text::BufferSnapshot::clip_offset_utf16)
4300    }
4301
4302    pub fn clip_point_utf16(&self, point: Unclipped<PointUtf16>, bias: Bias) -> PointUtf16 {
4303        self.clip_dimension(point.0, bias, |buffer, point, bias| {
4304            buffer.clip_point_utf16(Unclipped(point), bias)
4305        })
4306    }
4307
4308    pub fn offset_to_point(&self, offset: usize) -> Point {
4309        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point)
4310    }
4311
4312    pub fn offset_to_point_utf16(&self, offset: usize) -> PointUtf16 {
4313        self.convert_dimension(offset, text::BufferSnapshot::offset_to_point_utf16)
4314    }
4315
4316    pub fn point_to_point_utf16(&self, point: Point) -> PointUtf16 {
4317        self.convert_dimension(point, text::BufferSnapshot::point_to_point_utf16)
4318    }
4319
4320    pub fn point_to_offset(&self, point: Point) -> usize {
4321        self.convert_dimension(point, text::BufferSnapshot::point_to_offset)
4322    }
4323
4324    pub fn offset_utf16_to_offset(&self, offset: OffsetUtf16) -> usize {
4325        self.convert_dimension(offset, text::BufferSnapshot::offset_utf16_to_offset)
4326    }
4327
4328    pub fn offset_to_offset_utf16(&self, offset: usize) -> OffsetUtf16 {
4329        self.convert_dimension(offset, text::BufferSnapshot::offset_to_offset_utf16)
4330    }
4331
4332    pub fn point_utf16_to_offset(&self, point: PointUtf16) -> usize {
4333        self.convert_dimension(point, text::BufferSnapshot::point_utf16_to_offset)
4334    }
4335
4336    fn clip_dimension<D>(
4337        &self,
4338        position: D,
4339        bias: Bias,
4340        clip_buffer_position: fn(&text::BufferSnapshot, D, Bias) -> D,
4341    ) -> D
4342    where
4343        D: TextDimension + Ord + Sub<D, Output = D>,
4344    {
4345        let mut cursor = self.cursor();
4346        cursor.seek(&position);
4347        if let Some(region) = cursor.region() {
4348            if position >= region.range.end {
4349                return region.range.end;
4350            }
4351            let overshoot = position - region.range.start;
4352            let mut buffer_position = region.buffer_range.start;
4353            buffer_position.add_assign(&overshoot);
4354            let clipped_buffer_position =
4355                clip_buffer_position(&region.buffer, buffer_position, bias);
4356            let mut position = region.range.start;
4357            position.add_assign(&(clipped_buffer_position - region.buffer_range.start));
4358            position
4359        } else {
4360            D::from_text_summary(&self.text_summary())
4361        }
4362    }
4363
4364    fn convert_dimension<D1, D2>(
4365        &self,
4366        key: D1,
4367        convert_buffer_dimension: fn(&text::BufferSnapshot, D1) -> D2,
4368    ) -> D2
4369    where
4370        D1: TextDimension + Ord + Sub<D1, Output = D1>,
4371        D2: TextDimension + Ord + Sub<D2, Output = D2>,
4372    {
4373        let mut cursor = self.cursor::<DimensionPair<D1, D2>>();
4374        cursor.seek(&DimensionPair { key, value: None });
4375        if let Some(region) = cursor.region() {
4376            if key >= region.range.end.key {
4377                return region.range.end.value.unwrap();
4378            }
4379            let start_key = region.range.start.key;
4380            let start_value = region.range.start.value.unwrap();
4381            let buffer_start_key = region.buffer_range.start.key;
4382            let buffer_start_value = region.buffer_range.start.value.unwrap();
4383            let mut buffer_key = buffer_start_key;
4384            buffer_key.add_assign(&(key - start_key));
4385            let buffer_value = convert_buffer_dimension(&region.buffer, buffer_key);
4386            let mut result = start_value;
4387            result.add_assign(&(buffer_value - buffer_start_value));
4388            result
4389        } else {
4390            D2::from_text_summary(&self.text_summary())
4391        }
4392    }
4393
4394    pub fn point_to_buffer_offset<T: ToOffset>(
4395        &self,
4396        point: T,
4397    ) -> Option<(&BufferSnapshot, usize)> {
4398        let offset = point.to_offset(self);
4399        let mut cursor = self.cursor::<usize>();
4400        cursor.seek(&offset);
4401        let region = cursor.region()?;
4402        let overshoot = offset - region.range.start;
4403        let buffer_offset = region.buffer_range.start + overshoot;
4404        if buffer_offset == region.buffer.len() + 1
4405            && region.has_trailing_newline
4406            && !region.is_main_buffer
4407        {
4408            return Some((&cursor.excerpt()?.buffer, cursor.main_buffer_position()?));
4409        } else if buffer_offset > region.buffer.len() {
4410            return None;
4411        }
4412        Some((region.buffer, buffer_offset))
4413    }
4414
4415    pub fn point_to_buffer_point(
4416        &self,
4417        point: Point,
4418    ) -> Option<(&BufferSnapshot, Point, ExcerptId)> {
4419        let mut cursor = self.cursor::<Point>();
4420        cursor.seek(&point);
4421        let region = cursor.region()?;
4422        let overshoot = point - region.range.start;
4423        let buffer_point = region.buffer_range.start + overshoot;
4424        let excerpt = cursor.excerpt()?;
4425        if buffer_point == region.buffer.max_point() + Point::new(1, 0)
4426            && region.has_trailing_newline
4427            && !region.is_main_buffer
4428        {
4429            return Some((&excerpt.buffer, cursor.main_buffer_position()?, excerpt.id));
4430        } else if buffer_point > region.buffer.max_point() {
4431            return None;
4432        }
4433        Some((region.buffer, buffer_point, excerpt.id))
4434    }
4435
4436    pub fn suggested_indents(
4437        &self,
4438        rows: impl IntoIterator<Item = u32>,
4439        cx: &App,
4440    ) -> BTreeMap<MultiBufferRow, IndentSize> {
4441        let mut result = BTreeMap::new();
4442
4443        let mut rows_for_excerpt = Vec::new();
4444        let mut cursor = self.cursor::<Point>();
4445        let mut rows = rows.into_iter().peekable();
4446        let mut prev_row = u32::MAX;
4447        let mut prev_language_indent_size = IndentSize::default();
4448
4449        while let Some(row) = rows.next() {
4450            cursor.seek(&Point::new(row, 0));
4451            let Some(region) = cursor.region() else {
4452                continue;
4453            };
4454
4455            // Retrieve the language and indent size once for each disjoint region being indented.
4456            let single_indent_size = if row.saturating_sub(1) == prev_row {
4457                prev_language_indent_size
4458            } else {
4459                region
4460                    .buffer
4461                    .language_indent_size_at(Point::new(row, 0), cx)
4462            };
4463            prev_language_indent_size = single_indent_size;
4464            prev_row = row;
4465
4466            let start_buffer_row = region.buffer_range.start.row;
4467            let start_multibuffer_row = region.range.start.row;
4468            let end_multibuffer_row = region.range.end.row;
4469
4470            rows_for_excerpt.push(row);
4471            while let Some(next_row) = rows.peek().copied() {
4472                if end_multibuffer_row > next_row {
4473                    rows_for_excerpt.push(next_row);
4474                    rows.next();
4475                } else {
4476                    break;
4477                }
4478            }
4479
4480            let buffer_rows = rows_for_excerpt
4481                .drain(..)
4482                .map(|row| start_buffer_row + row - start_multibuffer_row);
4483            let buffer_indents = region
4484                .buffer
4485                .suggested_indents(buffer_rows, single_indent_size);
4486            let multibuffer_indents = buffer_indents.into_iter().map(|(row, indent)| {
4487                (
4488                    MultiBufferRow(start_multibuffer_row + row - start_buffer_row),
4489                    indent,
4490                )
4491            });
4492            result.extend(multibuffer_indents);
4493        }
4494
4495        result
4496    }
4497
4498    pub fn indent_size_for_line(&self, row: MultiBufferRow) -> IndentSize {
4499        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4500            let mut size = buffer.indent_size_for_line(range.start.row);
4501            size.len = size
4502                .len
4503                .min(range.end.column)
4504                .saturating_sub(range.start.column);
4505            size
4506        } else {
4507            IndentSize::spaces(0)
4508        }
4509    }
4510
4511    pub fn line_indent_for_row(&self, row: MultiBufferRow) -> LineIndent {
4512        if let Some((buffer, range)) = self.buffer_line_for_row(row) {
4513            LineIndent::from_iter(buffer.text_for_range(range).flat_map(|s| s.chars()))
4514        } else {
4515            LineIndent::spaces(0)
4516        }
4517    }
4518
4519    pub fn indent_and_comment_for_line(&self, row: MultiBufferRow, cx: &App) -> String {
4520        let mut indent = self.indent_size_for_line(row).chars().collect::<String>();
4521
4522        if self.language_settings(cx).extend_comment_on_newline {
4523            if let Some(language_scope) = self.language_scope_at(Point::new(row.0, 0)) {
4524                let delimiters = language_scope.line_comment_prefixes();
4525                for delimiter in delimiters {
4526                    if *self
4527                        .chars_at(Point::new(row.0, indent.len() as u32))
4528                        .take(delimiter.chars().count())
4529                        .collect::<String>()
4530                        .as_str()
4531                        == **delimiter
4532                    {
4533                        indent.push_str(&delimiter);
4534                        break;
4535                    }
4536                }
4537            }
4538        }
4539
4540        indent
4541    }
4542
4543    pub fn is_line_whitespace_upto<T>(&self, position: T) -> bool
4544    where
4545        T: ToOffset,
4546    {
4547        for char in self.reversed_chars_at(position) {
4548            if !char.is_whitespace() {
4549                return false;
4550            }
4551            if char == '\n' {
4552                return true;
4553            }
4554        }
4555        return true;
4556    }
4557
4558    pub fn prev_non_blank_row(&self, mut row: MultiBufferRow) -> Option<MultiBufferRow> {
4559        while row.0 > 0 {
4560            row.0 -= 1;
4561            if !self.is_line_blank(row) {
4562                return Some(row);
4563            }
4564        }
4565        None
4566    }
4567
4568    pub fn line_len(&self, row: MultiBufferRow) -> u32 {
4569        if let Some((_, range)) = self.buffer_line_for_row(row) {
4570            range.end.column - range.start.column
4571        } else {
4572            0
4573        }
4574    }
4575
4576    pub fn buffer_line_for_row(
4577        &self,
4578        row: MultiBufferRow,
4579    ) -> Option<(&BufferSnapshot, Range<Point>)> {
4580        let mut cursor = self.cursor::<Point>();
4581        let point = Point::new(row.0, 0);
4582        cursor.seek(&point);
4583        let region = cursor.region()?;
4584        let overshoot = point.min(region.range.end) - region.range.start;
4585        let buffer_point = region.buffer_range.start + overshoot;
4586        if buffer_point.row > region.buffer_range.end.row {
4587            return None;
4588        }
4589        let line_start = Point::new(buffer_point.row, 0).max(region.buffer_range.start);
4590        let line_end = Point::new(buffer_point.row, region.buffer.line_len(buffer_point.row))
4591            .min(region.buffer_range.end);
4592        Some((region.buffer, line_start..line_end))
4593    }
4594
4595    pub fn max_point(&self) -> Point {
4596        self.text_summary().lines
4597    }
4598
4599    pub fn max_row(&self) -> MultiBufferRow {
4600        MultiBufferRow(self.text_summary().lines.row)
4601    }
4602
4603    pub fn text_summary(&self) -> TextSummary {
4604        self.diff_transforms.summary().output
4605    }
4606
4607    pub fn text_summary_for_range<D, O>(&self, range: Range<O>) -> D
4608    where
4609        D: TextDimension,
4610        O: ToOffset,
4611    {
4612        let range = range.start.to_offset(self)..range.end.to_offset(self);
4613        let mut cursor = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
4614        cursor.seek(&range.start, Bias::Right, &());
4615
4616        let Some(first_transform) = cursor.item() else {
4617            return D::from_text_summary(&TextSummary::default());
4618        };
4619
4620        let diff_transform_start = cursor.start().0;
4621        let diff_transform_end = cursor.end(&()).0;
4622        let diff_start = range.start;
4623        let start_overshoot = diff_start - diff_transform_start;
4624        let end_overshoot = std::cmp::min(range.end, diff_transform_end) - diff_transform_start;
4625
4626        let mut result = match first_transform {
4627            DiffTransform::BufferContent { .. } => {
4628                let excerpt_start = cursor.start().1 + ExcerptOffset::new(start_overshoot);
4629                let excerpt_end = cursor.start().1 + ExcerptOffset::new(end_overshoot);
4630                self.text_summary_for_excerpt_offset_range(excerpt_start..excerpt_end)
4631            }
4632            DiffTransform::DeletedHunk {
4633                buffer_id,
4634                base_text_byte_range,
4635                has_trailing_newline,
4636                ..
4637            } => {
4638                let buffer_start = base_text_byte_range.start + start_overshoot;
4639                let mut buffer_end = base_text_byte_range.start + end_overshoot;
4640                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4641                    panic!("{:?} is in non-existent deleted hunk", range.start)
4642                };
4643
4644                let include_trailing_newline =
4645                    *has_trailing_newline && range.end >= diff_transform_end;
4646                if include_trailing_newline {
4647                    buffer_end -= 1;
4648                }
4649
4650                let mut summary =
4651                    base_text.text_summary_for_range::<D, _>(buffer_start..buffer_end);
4652
4653                if include_trailing_newline {
4654                    summary.add_assign(&D::from_text_summary(&TextSummary::newline()))
4655                }
4656
4657                summary
4658            }
4659        };
4660        if range.end < diff_transform_end {
4661            return result;
4662        }
4663
4664        cursor.next(&());
4665        result.add_assign(&D::from_text_summary(&cursor.summary(
4666            &range.end,
4667            Bias::Right,
4668            &(),
4669        )));
4670
4671        let Some(last_transform) = cursor.item() else {
4672            return result;
4673        };
4674
4675        let overshoot = range.end - cursor.start().0;
4676        let suffix = match last_transform {
4677            DiffTransform::BufferContent { .. } => {
4678                let end = cursor.start().1 + ExcerptOffset::new(overshoot);
4679                self.text_summary_for_excerpt_offset_range::<D>(cursor.start().1..end)
4680            }
4681            DiffTransform::DeletedHunk {
4682                base_text_byte_range,
4683                buffer_id,
4684                has_trailing_newline,
4685                ..
4686            } => {
4687                let buffer_end = base_text_byte_range.start + overshoot;
4688                let Some(base_text) = self.diffs.get(buffer_id).map(|diff| diff.base_text()) else {
4689                    panic!("{:?} is in non-existent deleted hunk", range.end)
4690                };
4691
4692                let mut suffix = base_text
4693                    .text_summary_for_range::<D, _>(base_text_byte_range.start..buffer_end);
4694                if *has_trailing_newline && buffer_end == base_text_byte_range.end + 1 {
4695                    suffix.add_assign(&D::from_text_summary(&TextSummary::newline()))
4696                }
4697                suffix
4698            }
4699        };
4700
4701        result.add_assign(&suffix);
4702        result
4703    }
4704
4705    fn text_summary_for_excerpt_offset_range<D>(&self, mut range: Range<ExcerptOffset>) -> D
4706    where
4707        D: TextDimension,
4708    {
4709        // let mut range = range.start..range.end;
4710        let mut summary = D::zero(&());
4711        let mut cursor = self.excerpts.cursor::<ExcerptOffset>(&());
4712        cursor.seek(&range.start, Bias::Right, &());
4713        if let Some(excerpt) = cursor.item() {
4714            let mut end_before_newline = cursor.end(&());
4715            if excerpt.has_trailing_newline {
4716                end_before_newline -= ExcerptOffset::new(1);
4717            }
4718
4719            let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4720            let start_in_excerpt = excerpt_start + (range.start - *cursor.start()).value;
4721            let end_in_excerpt =
4722                excerpt_start + (cmp::min(end_before_newline, range.end) - *cursor.start()).value;
4723            summary.add_assign(
4724                &excerpt
4725                    .buffer
4726                    .text_summary_for_range(start_in_excerpt..end_in_excerpt),
4727            );
4728
4729            if range.end > end_before_newline {
4730                summary.add_assign(&D::from_text_summary(&TextSummary::from("\n")));
4731            }
4732
4733            cursor.next(&());
4734        }
4735
4736        if range.end > *cursor.start() {
4737            summary.add_assign(
4738                &cursor
4739                    .summary::<_, ExcerptDimension<D>>(&range.end, Bias::Right, &())
4740                    .0,
4741            );
4742            if let Some(excerpt) = cursor.item() {
4743                range.end = cmp::max(*cursor.start(), range.end);
4744
4745                let excerpt_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
4746                let end_in_excerpt = excerpt_start + (range.end - *cursor.start()).value;
4747                summary.add_assign(
4748                    &excerpt
4749                        .buffer
4750                        .text_summary_for_range(excerpt_start..end_in_excerpt),
4751                );
4752            }
4753        }
4754
4755        summary
4756    }
4757
4758    pub fn summary_for_anchor<D>(&self, anchor: &Anchor) -> D
4759    where
4760        D: TextDimension + Ord + Sub<D, Output = D>,
4761    {
4762        self.summaries_for_anchors([anchor])[0]
4763    }
4764
4765    fn resolve_summary_for_anchor<D>(
4766        &self,
4767        anchor: &Anchor,
4768        excerpt_position: D,
4769        diff_transforms: &mut Cursor<DiffTransform, (ExcerptDimension<D>, OutputDimension<D>)>,
4770    ) -> D
4771    where
4772        D: TextDimension + Ord + Sub<D, Output = D>,
4773    {
4774        loop {
4775            let transform_end_position = diff_transforms.end(&()).0.0;
4776            let at_transform_end =
4777                excerpt_position == transform_end_position && diff_transforms.item().is_some();
4778            if at_transform_end && anchor.text_anchor.bias == Bias::Right {
4779                diff_transforms.next(&());
4780                continue;
4781            }
4782
4783            let mut position = diff_transforms.start().1.0;
4784            match diff_transforms.item() {
4785                Some(DiffTransform::DeletedHunk {
4786                    buffer_id,
4787                    base_text_byte_range,
4788                    ..
4789                }) => {
4790                    if let Some(diff_base_anchor) = &anchor.diff_base_anchor {
4791                        if let Some(base_text) =
4792                            self.diffs.get(buffer_id).map(|diff| diff.base_text())
4793                        {
4794                            if base_text.can_resolve(&diff_base_anchor) {
4795                                let base_text_offset = diff_base_anchor.to_offset(&base_text);
4796                                if base_text_offset >= base_text_byte_range.start
4797                                    && base_text_offset <= base_text_byte_range.end
4798                                {
4799                                    let position_in_hunk = base_text
4800                                        .text_summary_for_range::<D, _>(
4801                                            base_text_byte_range.start..base_text_offset,
4802                                        );
4803                                    position.add_assign(&position_in_hunk);
4804                                } else if at_transform_end {
4805                                    diff_transforms.next(&());
4806                                    continue;
4807                                }
4808                            }
4809                        }
4810                    }
4811                }
4812                _ => {
4813                    if at_transform_end && anchor.diff_base_anchor.is_some() {
4814                        diff_transforms.next(&());
4815                        continue;
4816                    }
4817                    let overshoot = excerpt_position - diff_transforms.start().0.0;
4818                    position.add_assign(&overshoot);
4819                }
4820            }
4821
4822            return position;
4823        }
4824    }
4825
4826    fn excerpt_offset_for_anchor(&self, anchor: &Anchor) -> ExcerptOffset {
4827        let mut cursor = self
4828            .excerpts
4829            .cursor::<(Option<&Locator>, ExcerptOffset)>(&());
4830        let locator = self.excerpt_locator_for_id(anchor.excerpt_id);
4831
4832        cursor.seek(&Some(locator), Bias::Left, &());
4833        if cursor.item().is_none() {
4834            cursor.next(&());
4835        }
4836
4837        let mut position = cursor.start().1;
4838        if let Some(excerpt) = cursor.item() {
4839            if excerpt.id == anchor.excerpt_id {
4840                let excerpt_buffer_start = excerpt
4841                    .buffer
4842                    .offset_for_anchor(&excerpt.range.context.start);
4843                let excerpt_buffer_end =
4844                    excerpt.buffer.offset_for_anchor(&excerpt.range.context.end);
4845                let buffer_position = cmp::min(
4846                    excerpt_buffer_end,
4847                    excerpt.buffer.offset_for_anchor(&anchor.text_anchor),
4848                );
4849                if buffer_position > excerpt_buffer_start {
4850                    position.value += buffer_position - excerpt_buffer_start;
4851                }
4852            }
4853        }
4854        position
4855    }
4856
4857    pub fn latest_excerpt_id(&self, mut excerpt_id: ExcerptId) -> ExcerptId {
4858        while let Some(replacement) = self.replaced_excerpts.get(&excerpt_id) {
4859            excerpt_id = *replacement;
4860        }
4861        return excerpt_id;
4862    }
4863
4864    pub fn summaries_for_anchors<'a, D, I>(&'a self, anchors: I) -> Vec<D>
4865    where
4866        D: TextDimension + Ord + Sub<D, Output = D>,
4867        I: 'a + IntoIterator<Item = &'a Anchor>,
4868    {
4869        let mut anchors = anchors.into_iter().peekable();
4870        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
4871        let mut diff_transforms_cursor = self
4872            .diff_transforms
4873            .cursor::<(ExcerptDimension<D>, OutputDimension<D>)>(&());
4874        diff_transforms_cursor.next(&());
4875
4876        let mut summaries = Vec::new();
4877        while let Some(anchor) = anchors.peek() {
4878            let excerpt_id = self.latest_excerpt_id(anchor.excerpt_id);
4879            let excerpt_anchors = iter::from_fn(|| {
4880                let anchor = anchors.peek()?;
4881                if self.latest_excerpt_id(anchor.excerpt_id) == excerpt_id {
4882                    Some(anchors.next().unwrap())
4883                } else {
4884                    None
4885                }
4886            });
4887
4888            let locator = self.excerpt_locator_for_id(excerpt_id);
4889            cursor.seek_forward(locator, Bias::Left, &());
4890            if cursor.item().is_none() {
4891                cursor.next(&());
4892            }
4893
4894            let excerpt_start_position = D::from_text_summary(&cursor.start().text);
4895            if let Some(excerpt) = cursor.item() {
4896                if excerpt.id != excerpt_id {
4897                    let position = self.resolve_summary_for_anchor(
4898                        &Anchor::min(),
4899                        excerpt_start_position,
4900                        &mut diff_transforms_cursor,
4901                    );
4902                    summaries.extend(excerpt_anchors.map(|_| position));
4903                    continue;
4904                }
4905                let excerpt_buffer_start =
4906                    excerpt.range.context.start.summary::<D>(&excerpt.buffer);
4907                let excerpt_buffer_end = excerpt.range.context.end.summary::<D>(&excerpt.buffer);
4908                for (buffer_summary, anchor) in excerpt
4909                    .buffer
4910                    .summaries_for_anchors_with_payload::<D, _, _>(
4911                        excerpt_anchors.map(|a| (&a.text_anchor, a)),
4912                    )
4913                {
4914                    let summary = cmp::min(excerpt_buffer_end, buffer_summary);
4915                    let mut position = excerpt_start_position;
4916                    if summary > excerpt_buffer_start {
4917                        position.add_assign(&(summary - excerpt_buffer_start));
4918                    }
4919
4920                    if position > diff_transforms_cursor.start().0.0 {
4921                        diff_transforms_cursor.seek_forward(
4922                            &ExcerptDimension(position),
4923                            Bias::Left,
4924                            &(),
4925                        );
4926                    }
4927
4928                    summaries.push(self.resolve_summary_for_anchor(
4929                        anchor,
4930                        position,
4931                        &mut diff_transforms_cursor,
4932                    ));
4933                }
4934            } else {
4935                diff_transforms_cursor.seek_forward(
4936                    &ExcerptDimension(excerpt_start_position),
4937                    Bias::Left,
4938                    &(),
4939                );
4940                let position = self.resolve_summary_for_anchor(
4941                    &Anchor::max(),
4942                    excerpt_start_position,
4943                    &mut diff_transforms_cursor,
4944                );
4945                summaries.extend(excerpt_anchors.map(|_| position));
4946            }
4947        }
4948
4949        summaries
4950    }
4951
4952    pub fn dimensions_from_points<'a, D>(
4953        &'a self,
4954        points: impl 'a + IntoIterator<Item = Point>,
4955    ) -> impl 'a + Iterator<Item = D>
4956    where
4957        D: TextDimension + Sub<D, Output = D>,
4958    {
4959        let mut cursor = self.cursor::<DimensionPair<Point, D>>();
4960        cursor.seek(&DimensionPair {
4961            key: Point::default(),
4962            value: None,
4963        });
4964        let mut points = points.into_iter();
4965        iter::from_fn(move || {
4966            let point = points.next()?;
4967
4968            cursor.seek_forward(&DimensionPair {
4969                key: point,
4970                value: None,
4971            });
4972
4973            if let Some(region) = cursor.region() {
4974                let overshoot = point - region.range.start.key;
4975                let buffer_point = region.buffer_range.start.key + overshoot;
4976                let mut position = region.range.start.value.unwrap();
4977                position.add_assign(
4978                    &region
4979                        .buffer
4980                        .text_summary_for_range(region.buffer_range.start.key..buffer_point),
4981                );
4982                if point == region.range.end.key && region.has_trailing_newline {
4983                    position.add_assign(&D::from_text_summary(&TextSummary::newline()));
4984                }
4985                return Some(position);
4986            } else {
4987                return Some(D::from_text_summary(&self.text_summary()));
4988            }
4989        })
4990    }
4991
4992    pub fn refresh_anchors<'a, I>(&'a self, anchors: I) -> Vec<(usize, Anchor, bool)>
4993    where
4994        I: 'a + IntoIterator<Item = &'a Anchor>,
4995    {
4996        let mut anchors = anchors.into_iter().enumerate().peekable();
4997        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
4998        cursor.next(&());
4999
5000        let mut result = Vec::new();
5001
5002        while let Some((_, anchor)) = anchors.peek() {
5003            let old_excerpt_id = anchor.excerpt_id;
5004
5005            // Find the location where this anchor's excerpt should be.
5006            let old_locator = self.excerpt_locator_for_id(old_excerpt_id);
5007            cursor.seek_forward(&Some(old_locator), Bias::Left, &());
5008
5009            if cursor.item().is_none() {
5010                cursor.next(&());
5011            }
5012
5013            let next_excerpt = cursor.item();
5014            let prev_excerpt = cursor.prev_item();
5015
5016            // Process all of the anchors for this excerpt.
5017            while let Some((_, anchor)) = anchors.peek() {
5018                if anchor.excerpt_id != old_excerpt_id {
5019                    break;
5020                }
5021                let (anchor_ix, anchor) = anchors.next().unwrap();
5022                let mut anchor = *anchor;
5023
5024                // Leave min and max anchors unchanged if invalid or
5025                // if the old excerpt still exists at this location
5026                let mut kept_position = next_excerpt
5027                    .map_or(false, |e| e.id == old_excerpt_id && e.contains(&anchor))
5028                    || old_excerpt_id == ExcerptId::max()
5029                    || old_excerpt_id == ExcerptId::min();
5030
5031                // If the old excerpt no longer exists at this location, then attempt to
5032                // find an equivalent position for this anchor in an adjacent excerpt.
5033                if !kept_position {
5034                    for excerpt in [next_excerpt, prev_excerpt].iter().filter_map(|e| *e) {
5035                        if excerpt.contains(&anchor) {
5036                            anchor.excerpt_id = excerpt.id;
5037                            kept_position = true;
5038                            break;
5039                        }
5040                    }
5041                }
5042
5043                // If there's no adjacent excerpt that contains the anchor's position,
5044                // then report that the anchor has lost its position.
5045                if !kept_position {
5046                    anchor = if let Some(excerpt) = next_excerpt {
5047                        let mut text_anchor = excerpt
5048                            .range
5049                            .context
5050                            .start
5051                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5052                        if text_anchor
5053                            .cmp(&excerpt.range.context.end, &excerpt.buffer)
5054                            .is_gt()
5055                        {
5056                            text_anchor = excerpt.range.context.end;
5057                        }
5058                        Anchor {
5059                            buffer_id: Some(excerpt.buffer_id),
5060                            excerpt_id: excerpt.id,
5061                            text_anchor,
5062                            diff_base_anchor: None,
5063                        }
5064                    } else if let Some(excerpt) = prev_excerpt {
5065                        let mut text_anchor = excerpt
5066                            .range
5067                            .context
5068                            .end
5069                            .bias(anchor.text_anchor.bias, &excerpt.buffer);
5070                        if text_anchor
5071                            .cmp(&excerpt.range.context.start, &excerpt.buffer)
5072                            .is_lt()
5073                        {
5074                            text_anchor = excerpt.range.context.start;
5075                        }
5076                        Anchor {
5077                            buffer_id: Some(excerpt.buffer_id),
5078                            excerpt_id: excerpt.id,
5079                            text_anchor,
5080                            diff_base_anchor: None,
5081                        }
5082                    } else if anchor.text_anchor.bias == Bias::Left {
5083                        Anchor::min()
5084                    } else {
5085                        Anchor::max()
5086                    };
5087                }
5088
5089                result.push((anchor_ix, anchor, kept_position));
5090            }
5091        }
5092        result.sort_unstable_by(|a, b| a.1.cmp(&b.1, self));
5093        result
5094    }
5095
5096    pub fn anchor_before<T: ToOffset>(&self, position: T) -> Anchor {
5097        self.anchor_at(position, Bias::Left)
5098    }
5099
5100    pub fn anchor_after<T: ToOffset>(&self, position: T) -> Anchor {
5101        self.anchor_at(position, Bias::Right)
5102    }
5103
5104    pub fn anchor_at<T: ToOffset>(&self, position: T, mut bias: Bias) -> Anchor {
5105        let offset = position.to_offset(self);
5106
5107        // Find the given position in the diff transforms. Determine the corresponding
5108        // offset in the excerpts, and whether the position is within a deleted hunk.
5109        let mut diff_transforms = self.diff_transforms.cursor::<(usize, ExcerptOffset)>(&());
5110        diff_transforms.seek(&offset, Bias::Right, &());
5111
5112        if offset == diff_transforms.start().0 && bias == Bias::Left {
5113            if let Some(prev_item) = diff_transforms.prev_item() {
5114                match prev_item {
5115                    DiffTransform::DeletedHunk { .. } => {
5116                        diff_transforms.prev(&());
5117                    }
5118                    _ => {}
5119                }
5120            }
5121        }
5122        let offset_in_transform = offset - diff_transforms.start().0;
5123        let mut excerpt_offset = diff_transforms.start().1;
5124        let mut diff_base_anchor = None;
5125        if let Some(DiffTransform::DeletedHunk {
5126            buffer_id,
5127            base_text_byte_range,
5128            has_trailing_newline,
5129            ..
5130        }) = diff_transforms.item()
5131        {
5132            let diff = self.diffs.get(buffer_id).expect("missing diff");
5133            if offset_in_transform > base_text_byte_range.len() {
5134                debug_assert!(*has_trailing_newline);
5135                bias = Bias::Right;
5136            } else {
5137                diff_base_anchor = Some(
5138                    diff.base_text()
5139                        .anchor_at(base_text_byte_range.start + offset_in_transform, bias),
5140                );
5141                bias = Bias::Left;
5142            }
5143        } else {
5144            excerpt_offset += ExcerptOffset::new(offset_in_transform);
5145        };
5146
5147        if let Some((excerpt_id, buffer_id, buffer)) = self.as_singleton() {
5148            return Anchor {
5149                buffer_id: Some(buffer_id),
5150                excerpt_id: *excerpt_id,
5151                text_anchor: buffer.anchor_at(excerpt_offset.value, bias),
5152                diff_base_anchor,
5153            };
5154        }
5155
5156        let mut excerpts = self
5157            .excerpts
5158            .cursor::<(ExcerptOffset, Option<ExcerptId>)>(&());
5159        excerpts.seek(&excerpt_offset, Bias::Right, &());
5160        if excerpts.item().is_none() && excerpt_offset == excerpts.start().0 && bias == Bias::Left {
5161            excerpts.prev(&());
5162        }
5163        if let Some(excerpt) = excerpts.item() {
5164            let mut overshoot = excerpt_offset.saturating_sub(excerpts.start().0).value;
5165            if excerpt.has_trailing_newline && excerpt_offset == excerpts.end(&()).0 {
5166                overshoot -= 1;
5167                bias = Bias::Right;
5168            }
5169
5170            let buffer_start = excerpt.range.context.start.to_offset(&excerpt.buffer);
5171            let text_anchor =
5172                excerpt.clip_anchor(excerpt.buffer.anchor_at(buffer_start + overshoot, bias));
5173            Anchor {
5174                buffer_id: Some(excerpt.buffer_id),
5175                excerpt_id: excerpt.id,
5176                text_anchor,
5177                diff_base_anchor,
5178            }
5179        } else if excerpt_offset.is_zero() && bias == Bias::Left {
5180            Anchor::min()
5181        } else {
5182            Anchor::max()
5183        }
5184    }
5185
5186    /// Returns an anchor for the given excerpt and text anchor,
5187    /// returns None if the excerpt_id is no longer valid.
5188    pub fn anchor_in_excerpt(
5189        &self,
5190        excerpt_id: ExcerptId,
5191        text_anchor: text::Anchor,
5192    ) -> Option<Anchor> {
5193        let locator = self.excerpt_locator_for_id(excerpt_id);
5194        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
5195        cursor.seek(locator, Bias::Left, &());
5196        if let Some(excerpt) = cursor.item() {
5197            if excerpt.id == excerpt_id {
5198                let text_anchor = excerpt.clip_anchor(text_anchor);
5199                drop(cursor);
5200                return Some(Anchor {
5201                    buffer_id: Some(excerpt.buffer_id),
5202                    excerpt_id,
5203                    text_anchor,
5204                    diff_base_anchor: None,
5205                });
5206            }
5207        }
5208        None
5209    }
5210
5211    pub fn context_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
5212        Some(self.excerpt(excerpt_id)?.range.context.clone())
5213    }
5214
5215    pub fn can_resolve(&self, anchor: &Anchor) -> bool {
5216        if anchor.excerpt_id == ExcerptId::min() || anchor.excerpt_id == ExcerptId::max() {
5217            true
5218        } else if let Some(excerpt) = self.excerpt(anchor.excerpt_id) {
5219            excerpt.buffer.can_resolve(&anchor.text_anchor)
5220        } else {
5221            false
5222        }
5223    }
5224
5225    pub fn excerpts(
5226        &self,
5227    ) -> impl Iterator<Item = (ExcerptId, &BufferSnapshot, ExcerptRange<text::Anchor>)> {
5228        self.excerpts
5229            .iter()
5230            .map(|excerpt| (excerpt.id, &excerpt.buffer, excerpt.range.clone()))
5231    }
5232
5233    fn cursor<D: TextDimension + Default>(&self) -> MultiBufferCursor<D> {
5234        let excerpts = self.excerpts.cursor(&());
5235        let diff_transforms = self.diff_transforms.cursor(&());
5236        MultiBufferCursor {
5237            excerpts,
5238            diff_transforms,
5239            diffs: &self.diffs,
5240            cached_region: None,
5241        }
5242    }
5243
5244    pub fn excerpt_before(&self, id: ExcerptId) -> Option<MultiBufferExcerpt<'_>> {
5245        let start_locator = self.excerpt_locator_for_id(id);
5246        let mut excerpts = self
5247            .excerpts
5248            .cursor::<(Option<&Locator>, ExcerptDimension<usize>)>(&());
5249        excerpts.seek(&Some(start_locator), Bias::Left, &());
5250        excerpts.prev(&());
5251
5252        let mut diff_transforms = self
5253            .diff_transforms
5254            .cursor::<(OutputDimension<usize>, ExcerptDimension<usize>)>(&());
5255        diff_transforms.seek(&excerpts.start().1, Bias::Left, &());
5256        if diff_transforms.end(&()).1 < excerpts.start().1 {
5257            diff_transforms.next(&());
5258        }
5259
5260        let excerpt = excerpts.item()?;
5261        Some(MultiBufferExcerpt {
5262            excerpt,
5263            offset: diff_transforms.start().0.0,
5264            buffer_offset: excerpt.range.context.start.to_offset(&excerpt.buffer),
5265            excerpt_offset: excerpts.start().1.clone(),
5266            diff_transforms,
5267        })
5268    }
5269
5270    pub fn excerpt_boundaries_in_range<R, T>(
5271        &self,
5272        range: R,
5273    ) -> impl Iterator<Item = ExcerptBoundary> + '_
5274    where
5275        R: RangeBounds<T>,
5276        T: ToOffset,
5277    {
5278        let start_offset;
5279        let start = match range.start_bound() {
5280            Bound::Included(start) => {
5281                start_offset = start.to_offset(self);
5282                Bound::Included(start_offset)
5283            }
5284            Bound::Excluded(_) => {
5285                panic!("not supported")
5286            }
5287            Bound::Unbounded => {
5288                start_offset = 0;
5289                Bound::Unbounded
5290            }
5291        };
5292        let end = match range.end_bound() {
5293            Bound::Included(end) => Bound::Included(end.to_offset(self)),
5294            Bound::Excluded(end) => Bound::Excluded(end.to_offset(self)),
5295            Bound::Unbounded => Bound::Unbounded,
5296        };
5297        let bounds = (start, end);
5298
5299        let mut cursor = self.cursor::<DimensionPair<usize, Point>>();
5300        cursor.seek(&DimensionPair {
5301            key: start_offset,
5302            value: None,
5303        });
5304
5305        if cursor
5306            .region()
5307            .is_some_and(|region| bounds.contains(&region.range.start.key))
5308        {
5309            cursor.prev_excerpt();
5310        } else {
5311            cursor.seek_to_start_of_current_excerpt();
5312        }
5313        let mut prev_region = cursor.region();
5314
5315        cursor.next_excerpt();
5316
5317        iter::from_fn(move || {
5318            loop {
5319                if self.singleton {
5320                    return None;
5321                }
5322
5323                let next_region = cursor.region()?;
5324                cursor.next_excerpt();
5325                if !bounds.contains(&next_region.range.start.key) {
5326                    prev_region = Some(next_region);
5327                    continue;
5328                }
5329
5330                let next_region_start = next_region.range.start.value.unwrap();
5331                let next_region_end = if let Some(region) = cursor.region() {
5332                    region.range.start.value.unwrap()
5333                } else {
5334                    self.max_point()
5335                };
5336
5337                let prev = prev_region.as_ref().map(|region| ExcerptInfo {
5338                    id: region.excerpt.id,
5339                    buffer: region.excerpt.buffer.clone(),
5340                    buffer_id: region.excerpt.buffer_id,
5341                    range: region.excerpt.range.clone(),
5342                    end_row: MultiBufferRow(next_region_start.row),
5343                });
5344
5345                let next = ExcerptInfo {
5346                    id: next_region.excerpt.id,
5347                    buffer: next_region.excerpt.buffer.clone(),
5348                    buffer_id: next_region.excerpt.buffer_id,
5349                    range: next_region.excerpt.range.clone(),
5350                    end_row: if next_region.excerpt.has_trailing_newline {
5351                        MultiBufferRow(next_region_end.row - 1)
5352                    } else {
5353                        MultiBufferRow(next_region_end.row)
5354                    },
5355                };
5356
5357                let row = MultiBufferRow(next_region_start.row);
5358
5359                prev_region = Some(next_region);
5360
5361                return Some(ExcerptBoundary { row, prev, next });
5362            }
5363        })
5364    }
5365
5366    pub fn edit_count(&self) -> usize {
5367        self.edit_count
5368    }
5369
5370    pub fn non_text_state_update_count(&self) -> usize {
5371        self.non_text_state_update_count
5372    }
5373
5374    /// Returns the smallest enclosing bracket ranges containing the given range or
5375    /// None if no brackets contain range or the range is not contained in a single
5376    /// excerpt
5377    ///
5378    /// Can optionally pass a range_filter to filter the ranges of brackets to consider
5379    pub fn innermost_enclosing_bracket_ranges<T: ToOffset>(
5380        &self,
5381        range: Range<T>,
5382        range_filter: Option<&dyn Fn(&BufferSnapshot, Range<usize>, Range<usize>) -> bool>,
5383    ) -> Option<(Range<usize>, Range<usize>)> {
5384        let range = range.start.to_offset(self)..range.end.to_offset(self);
5385        let mut excerpt = self.excerpt_containing(range.clone())?;
5386        let buffer = excerpt.buffer();
5387        let excerpt_buffer_range = excerpt.buffer_range();
5388
5389        // Filter to ranges contained in the excerpt
5390        let range_filter = |open: Range<usize>, close: Range<usize>| -> bool {
5391            excerpt_buffer_range.contains(&open.start)
5392                && excerpt_buffer_range.contains(&close.end)
5393                && range_filter.map_or(true, |filter| filter(buffer, open, close))
5394        };
5395
5396        let (open, close) = excerpt.buffer().innermost_enclosing_bracket_ranges(
5397            excerpt.map_range_to_buffer(range),
5398            Some(&range_filter),
5399        )?;
5400
5401        Some((
5402            excerpt.map_range_from_buffer(open),
5403            excerpt.map_range_from_buffer(close),
5404        ))
5405    }
5406
5407    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5408    /// not contained in a single excerpt
5409    pub fn enclosing_bracket_ranges<T: ToOffset>(
5410        &self,
5411        range: Range<T>,
5412    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5413        let range = range.start.to_offset(self)..range.end.to_offset(self);
5414        let mut excerpt = self.excerpt_containing(range.clone())?;
5415
5416        Some(
5417            excerpt
5418                .buffer()
5419                .enclosing_bracket_ranges(excerpt.map_range_to_buffer(range))
5420                .filter_map(move |pair| {
5421                    if excerpt.contains_buffer_range(pair.open_range.start..pair.close_range.end) {
5422                        Some((
5423                            excerpt.map_range_from_buffer(pair.open_range),
5424                            excerpt.map_range_from_buffer(pair.close_range),
5425                        ))
5426                    } else {
5427                        None
5428                    }
5429                }),
5430        )
5431    }
5432
5433    /// Returns enclosing bracket ranges containing the given range or returns None if the range is
5434    /// not contained in a single excerpt
5435    pub fn text_object_ranges<T: ToOffset>(
5436        &self,
5437        range: Range<T>,
5438        options: TreeSitterOptions,
5439    ) -> impl Iterator<Item = (Range<usize>, TextObject)> + '_ {
5440        let range = range.start.to_offset(self)..range.end.to_offset(self);
5441        self.excerpt_containing(range.clone())
5442            .map(|mut excerpt| {
5443                excerpt
5444                    .buffer()
5445                    .text_object_ranges(excerpt.map_range_to_buffer(range), options)
5446                    .filter_map(move |(range, text_object)| {
5447                        if excerpt.contains_buffer_range(range.clone()) {
5448                            Some((excerpt.map_range_from_buffer(range), text_object))
5449                        } else {
5450                            None
5451                        }
5452                    })
5453            })
5454            .into_iter()
5455            .flatten()
5456    }
5457
5458    /// Returns bracket range pairs overlapping the given `range` or returns None if the `range` is
5459    /// not contained in a single excerpt
5460    pub fn bracket_ranges<T: ToOffset>(
5461        &self,
5462        range: Range<T>,
5463    ) -> Option<impl Iterator<Item = (Range<usize>, Range<usize>)> + '_> {
5464        let range = range.start.to_offset(self)..range.end.to_offset(self);
5465        let mut excerpt = self.excerpt_containing(range.clone())?;
5466
5467        Some(
5468            excerpt
5469                .buffer()
5470                .bracket_ranges(excerpt.map_range_to_buffer(range))
5471                .filter_map(move |pair| {
5472                    let buffer_range = pair.open_range.start..pair.close_range.end;
5473                    if excerpt.contains_buffer_range(buffer_range) {
5474                        Some((
5475                            excerpt.map_range_from_buffer(pair.open_range),
5476                            excerpt.map_range_from_buffer(pair.close_range),
5477                        ))
5478                    } else {
5479                        None
5480                    }
5481                }),
5482        )
5483    }
5484
5485    pub fn redacted_ranges<'a, T: ToOffset>(
5486        &'a self,
5487        range: Range<T>,
5488        redaction_enabled: impl Fn(Option<&Arc<dyn File>>) -> bool + 'a,
5489    ) -> impl Iterator<Item = Range<usize>> + 'a {
5490        let range = range.start.to_offset(self)..range.end.to_offset(self);
5491        self.lift_buffer_metadata(range, move |buffer, range| {
5492            if redaction_enabled(buffer.file()) {
5493                Some(buffer.redacted_ranges(range).map(|range| (range, ())))
5494            } else {
5495                None
5496            }
5497        })
5498        .map(|(range, _, _)| range)
5499    }
5500
5501    pub fn runnable_ranges(
5502        &self,
5503        range: Range<Anchor>,
5504    ) -> impl Iterator<Item = language::RunnableRange> + '_ {
5505        let range = range.start.to_offset(self)..range.end.to_offset(self);
5506        self.lift_buffer_metadata(range, move |buffer, range| {
5507            Some(
5508                buffer
5509                    .runnable_ranges(range.clone())
5510                    .filter(move |runnable| {
5511                        runnable.run_range.start >= range.start
5512                            && runnable.run_range.end < range.end
5513                    })
5514                    .map(|runnable| (runnable.run_range.clone(), runnable)),
5515            )
5516        })
5517        .map(|(run_range, runnable, _)| language::RunnableRange {
5518            run_range,
5519            ..runnable
5520        })
5521    }
5522
5523    pub fn line_indents(
5524        &self,
5525        start_row: MultiBufferRow,
5526        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5527    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5528        let max_point = self.max_point();
5529        let mut cursor = self.cursor::<Point>();
5530        cursor.seek(&Point::new(start_row.0, 0));
5531        iter::from_fn(move || {
5532            let mut region = cursor.region()?;
5533            while !buffer_filter(&region.excerpt.buffer) {
5534                cursor.next();
5535                region = cursor.region()?;
5536            }
5537            let overshoot = start_row.0.saturating_sub(region.range.start.row);
5538            let buffer_start_row =
5539                (region.buffer_range.start.row + overshoot).min(region.buffer_range.end.row);
5540
5541            let buffer_end_row = if region.is_main_buffer
5542                && (region.has_trailing_newline || region.range.end == max_point)
5543            {
5544                region.buffer_range.end.row
5545            } else {
5546                region.buffer_range.end.row.saturating_sub(1)
5547            };
5548
5549            let line_indents = region
5550                .buffer
5551                .line_indents_in_row_range(buffer_start_row..buffer_end_row);
5552            cursor.next();
5553            return Some(line_indents.map(move |(buffer_row, indent)| {
5554                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5555                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5556            }));
5557        })
5558        .flatten()
5559    }
5560
5561    pub fn reversed_line_indents(
5562        &self,
5563        end_row: MultiBufferRow,
5564        buffer_filter: impl Fn(&BufferSnapshot) -> bool,
5565    ) -> impl Iterator<Item = (MultiBufferRow, LineIndent, &BufferSnapshot)> {
5566        let max_point = self.max_point();
5567        let mut cursor = self.cursor::<Point>();
5568        cursor.seek(&Point::new(end_row.0, 0));
5569        iter::from_fn(move || {
5570            let mut region = cursor.region()?;
5571            while !buffer_filter(&region.excerpt.buffer) {
5572                cursor.prev();
5573                region = cursor.region()?;
5574            }
5575
5576            let buffer_start_row = region.buffer_range.start.row;
5577            let buffer_end_row = if region.is_main_buffer
5578                && (region.has_trailing_newline || region.range.end == max_point)
5579            {
5580                region.buffer_range.end.row + 1
5581            } else {
5582                region.buffer_range.end.row
5583            };
5584
5585            let overshoot = end_row.0 - region.range.start.row;
5586            let buffer_end_row =
5587                (region.buffer_range.start.row + overshoot + 1).min(buffer_end_row);
5588
5589            let line_indents = region
5590                .buffer
5591                .reversed_line_indents_in_row_range(buffer_start_row..buffer_end_row);
5592            cursor.prev();
5593            return Some(line_indents.map(move |(buffer_row, indent)| {
5594                let row = region.range.start.row + (buffer_row - region.buffer_range.start.row);
5595                (MultiBufferRow(row), indent, &region.excerpt.buffer)
5596            }));
5597        })
5598        .flatten()
5599    }
5600
5601    pub async fn enclosing_indent(
5602        &self,
5603        mut target_row: MultiBufferRow,
5604    ) -> Option<(Range<MultiBufferRow>, LineIndent)> {
5605        let max_row = MultiBufferRow(self.max_point().row);
5606        if target_row >= max_row {
5607            return None;
5608        }
5609
5610        let mut target_indent = self.line_indent_for_row(target_row);
5611
5612        // If the current row is at the start of an indented block, we want to return this
5613        // block as the enclosing indent.
5614        if !target_indent.is_line_empty() && target_row < max_row {
5615            let next_line_indent = self.line_indent_for_row(MultiBufferRow(target_row.0 + 1));
5616            if !next_line_indent.is_line_empty()
5617                && target_indent.raw_len() < next_line_indent.raw_len()
5618            {
5619                target_indent = next_line_indent;
5620                target_row.0 += 1;
5621            }
5622        }
5623
5624        const SEARCH_ROW_LIMIT: u32 = 25000;
5625        const SEARCH_WHITESPACE_ROW_LIMIT: u32 = 2500;
5626        const YIELD_INTERVAL: u32 = 100;
5627
5628        let mut accessed_row_counter = 0;
5629
5630        // If there is a blank line at the current row, search for the next non indented lines
5631        if target_indent.is_line_empty() {
5632            let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_WHITESPACE_ROW_LIMIT));
5633            let end =
5634                MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_WHITESPACE_ROW_LIMIT));
5635
5636            let mut non_empty_line_above = None;
5637            for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5638                if row < start {
5639                    break;
5640                }
5641                accessed_row_counter += 1;
5642                if accessed_row_counter == YIELD_INTERVAL {
5643                    accessed_row_counter = 0;
5644                    yield_now().await;
5645                }
5646                if !indent.is_line_empty() {
5647                    non_empty_line_above = Some((row, indent));
5648                    break;
5649                }
5650            }
5651
5652            let mut non_empty_line_below = None;
5653            for (row, indent, _) in self.line_indents(target_row, |_| true) {
5654                if row > end {
5655                    break;
5656                }
5657                accessed_row_counter += 1;
5658                if accessed_row_counter == YIELD_INTERVAL {
5659                    accessed_row_counter = 0;
5660                    yield_now().await;
5661                }
5662                if !indent.is_line_empty() {
5663                    non_empty_line_below = Some((row, indent));
5664                    break;
5665                }
5666            }
5667
5668            let (row, indent) = match (non_empty_line_above, non_empty_line_below) {
5669                (Some((above_row, above_indent)), Some((below_row, below_indent))) => {
5670                    if above_indent.raw_len() >= below_indent.raw_len() {
5671                        (above_row, above_indent)
5672                    } else {
5673                        (below_row, below_indent)
5674                    }
5675                }
5676                (Some(above), None) => above,
5677                (None, Some(below)) => below,
5678                _ => return None,
5679            };
5680
5681            target_indent = indent;
5682            target_row = row;
5683        }
5684
5685        let start = MultiBufferRow(target_row.0.saturating_sub(SEARCH_ROW_LIMIT));
5686        let end = MultiBufferRow((max_row.0 + 1).min(target_row.0 + SEARCH_ROW_LIMIT));
5687
5688        let mut start_indent = None;
5689        for (row, indent, _) in self.reversed_line_indents(target_row, |_| true) {
5690            if row < start {
5691                break;
5692            }
5693            accessed_row_counter += 1;
5694            if accessed_row_counter == YIELD_INTERVAL {
5695                accessed_row_counter = 0;
5696                yield_now().await;
5697            }
5698            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5699                start_indent = Some((row, indent));
5700                break;
5701            }
5702        }
5703        let (start_row, start_indent_size) = start_indent?;
5704
5705        let mut end_indent = (end, None);
5706        for (row, indent, _) in self.line_indents(target_row, |_| true) {
5707            if row > end {
5708                break;
5709            }
5710            accessed_row_counter += 1;
5711            if accessed_row_counter == YIELD_INTERVAL {
5712                accessed_row_counter = 0;
5713                yield_now().await;
5714            }
5715            if !indent.is_line_empty() && indent.raw_len() < target_indent.raw_len() {
5716                end_indent = (MultiBufferRow(row.0.saturating_sub(1)), Some(indent));
5717                break;
5718            }
5719        }
5720        let (end_row, end_indent_size) = end_indent;
5721
5722        let indent = if let Some(end_indent_size) = end_indent_size {
5723            if start_indent_size.raw_len() > end_indent_size.raw_len() {
5724                start_indent_size
5725            } else {
5726                end_indent_size
5727            }
5728        } else {
5729            start_indent_size
5730        };
5731
5732        Some((start_row..end_row, indent))
5733    }
5734
5735    pub fn indent_guides_in_range<T: ToPoint>(
5736        &self,
5737        range: Range<T>,
5738        ignore_disabled_for_language: bool,
5739        cx: &App,
5740    ) -> impl Iterator<Item = IndentGuide> {
5741        let range = range.start.to_point(self)..range.end.to_point(self);
5742        let start_row = MultiBufferRow(range.start.row);
5743        let end_row = MultiBufferRow(range.end.row);
5744
5745        let mut row_indents = self.line_indents(start_row, |buffer| {
5746            let settings =
5747                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5748            settings.indent_guides.enabled || ignore_disabled_for_language
5749        });
5750
5751        let mut result = Vec::new();
5752        let mut indent_stack = SmallVec::<[IndentGuide; 8]>::new();
5753
5754        while let Some((first_row, mut line_indent, buffer)) = row_indents.next() {
5755            if first_row > end_row {
5756                break;
5757            }
5758            let current_depth = indent_stack.len() as u32;
5759
5760            let settings =
5761                language_settings(buffer.language().map(|l| l.name()), buffer.file(), cx);
5762            let tab_size = settings.tab_size.get() as u32;
5763
5764            // When encountering empty, continue until found useful line indent
5765            // then add to the indent stack with the depth found
5766            let mut found_indent = false;
5767            let mut last_row = first_row;
5768            if line_indent.is_line_empty() {
5769                while !found_indent {
5770                    let Some((target_row, new_line_indent, _)) = row_indents.next() else {
5771                        break;
5772                    };
5773                    const TRAILING_ROW_SEARCH_LIMIT: u32 = 25;
5774                    if target_row > MultiBufferRow(end_row.0 + TRAILING_ROW_SEARCH_LIMIT) {
5775                        break;
5776                    }
5777
5778                    if new_line_indent.is_line_empty() {
5779                        continue;
5780                    }
5781                    last_row = target_row.min(end_row);
5782                    line_indent = new_line_indent;
5783                    found_indent = true;
5784                    break;
5785                }
5786            } else {
5787                found_indent = true
5788            }
5789
5790            let depth = if found_indent {
5791                line_indent.len(tab_size) / tab_size
5792                    + ((line_indent.len(tab_size) % tab_size) > 0) as u32
5793            } else {
5794                current_depth
5795            };
5796
5797            match depth.cmp(&current_depth) {
5798                cmp::Ordering::Less => {
5799                    for _ in 0..(current_depth - depth) {
5800                        let mut indent = indent_stack.pop().unwrap();
5801                        if last_row != first_row {
5802                            // In this case, we landed on an empty row, had to seek forward,
5803                            // and discovered that the indent we where on is ending.
5804                            // This means that the last display row must
5805                            // be on line that ends this indent range, so we
5806                            // should display the range up to the first non-empty line
5807                            indent.end_row = MultiBufferRow(first_row.0.saturating_sub(1));
5808                        }
5809
5810                        result.push(indent)
5811                    }
5812                }
5813                cmp::Ordering::Greater => {
5814                    for next_depth in current_depth..depth {
5815                        indent_stack.push(IndentGuide {
5816                            buffer_id: buffer.remote_id(),
5817                            start_row: first_row,
5818                            end_row: last_row,
5819                            depth: next_depth,
5820                            tab_size,
5821                            settings: settings.indent_guides,
5822                        });
5823                    }
5824                }
5825                _ => {}
5826            }
5827
5828            for indent in indent_stack.iter_mut() {
5829                indent.end_row = last_row;
5830            }
5831        }
5832
5833        result.extend(indent_stack);
5834        result.into_iter()
5835    }
5836
5837    pub fn trailing_excerpt_update_count(&self) -> usize {
5838        self.trailing_excerpt_update_count
5839    }
5840
5841    pub fn file_at<T: ToOffset>(&self, point: T) -> Option<&Arc<dyn File>> {
5842        self.point_to_buffer_offset(point)
5843            .and_then(|(buffer, _)| buffer.file())
5844    }
5845
5846    pub fn language_at<T: ToOffset>(&self, point: T) -> Option<&Arc<Language>> {
5847        self.point_to_buffer_offset(point)
5848            .and_then(|(buffer, offset)| buffer.language_at(offset))
5849    }
5850
5851    fn language_settings<'a>(&'a self, cx: &'a App) -> Cow<'a, LanguageSettings> {
5852        self.excerpts
5853            .first()
5854            .map(|excerpt| &excerpt.buffer)
5855            .map(|buffer| {
5856                language_settings(
5857                    buffer.language().map(|language| language.name()),
5858                    buffer.file(),
5859                    cx,
5860                )
5861            })
5862            .unwrap_or_else(move || self.language_settings_at(0, cx))
5863    }
5864
5865    pub fn language_settings_at<'a, T: ToOffset>(
5866        &'a self,
5867        point: T,
5868        cx: &'a App,
5869    ) -> Cow<'a, LanguageSettings> {
5870        let mut language = None;
5871        let mut file = None;
5872        if let Some((buffer, offset)) = self.point_to_buffer_offset(point) {
5873            language = buffer.language_at(offset);
5874            file = buffer.file();
5875        }
5876        language_settings(language.map(|l| l.name()), file, cx)
5877    }
5878
5879    pub fn language_scope_at<T: ToOffset>(&self, point: T) -> Option<LanguageScope> {
5880        self.point_to_buffer_offset(point)
5881            .and_then(|(buffer, offset)| buffer.language_scope_at(offset))
5882    }
5883
5884    pub fn char_classifier_at<T: ToOffset>(&self, point: T) -> CharClassifier {
5885        self.point_to_buffer_offset(point)
5886            .map(|(buffer, offset)| buffer.char_classifier_at(offset))
5887            .unwrap_or_default()
5888    }
5889
5890    pub fn language_indent_size_at<T: ToOffset>(
5891        &self,
5892        position: T,
5893        cx: &App,
5894    ) -> Option<IndentSize> {
5895        let (buffer_snapshot, offset) = self.point_to_buffer_offset(position)?;
5896        Some(buffer_snapshot.language_indent_size_at(offset, cx))
5897    }
5898
5899    pub fn is_dirty(&self) -> bool {
5900        self.is_dirty
5901    }
5902
5903    pub fn has_deleted_file(&self) -> bool {
5904        self.has_deleted_file
5905    }
5906
5907    pub fn has_conflict(&self) -> bool {
5908        self.has_conflict
5909    }
5910
5911    pub fn has_diagnostics(&self) -> bool {
5912        self.excerpts
5913            .iter()
5914            .any(|excerpt| excerpt.buffer.has_diagnostics())
5915    }
5916
5917    pub fn diagnostic_group(
5918        &self,
5919        buffer_id: BufferId,
5920        group_id: usize,
5921    ) -> impl Iterator<Item = DiagnosticEntry<Point>> + '_ {
5922        self.lift_buffer_metadata(Point::zero()..self.max_point(), move |buffer, _| {
5923            if buffer.remote_id() != buffer_id {
5924                return None;
5925            };
5926            Some(
5927                buffer
5928                    .diagnostic_group(group_id)
5929                    .map(move |DiagnosticEntry { diagnostic, range }| (range, diagnostic)),
5930            )
5931        })
5932        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5933    }
5934
5935    pub fn diagnostics_in_range<'a, T>(
5936        &'a self,
5937        range: Range<T>,
5938    ) -> impl Iterator<Item = DiagnosticEntry<T>> + 'a
5939    where
5940        T: 'a
5941            + text::ToOffset
5942            + text::FromAnchor
5943            + TextDimension
5944            + Ord
5945            + Sub<T, Output = T>
5946            + fmt::Debug,
5947    {
5948        self.lift_buffer_metadata(range, move |buffer, buffer_range| {
5949            Some(
5950                buffer
5951                    .diagnostics_in_range(buffer_range.start..buffer_range.end, false)
5952                    .map(|entry| (entry.range, entry.diagnostic)),
5953            )
5954        })
5955        .map(|(range, diagnostic, _)| DiagnosticEntry { diagnostic, range })
5956    }
5957
5958    pub fn syntax_ancestor<T: ToOffset>(
5959        &self,
5960        range: Range<T>,
5961    ) -> Option<(tree_sitter::Node, MultiOrSingleBufferOffsetRange)> {
5962        let range = range.start.to_offset(self)..range.end.to_offset(self);
5963        let mut excerpt = self.excerpt_containing(range.clone())?;
5964        let node = excerpt
5965            .buffer()
5966            .syntax_ancestor(excerpt.map_range_to_buffer(range))?;
5967        let node_range = node.byte_range();
5968        let range = if excerpt.contains_buffer_range(node_range.clone()) {
5969            MultiOrSingleBufferOffsetRange::Multi(excerpt.map_range_from_buffer(node_range))
5970        } else {
5971            MultiOrSingleBufferOffsetRange::Single(node_range)
5972        };
5973        Some((node, range))
5974    }
5975
5976    pub fn outline(&self, theme: Option<&SyntaxTheme>) -> Option<Outline<Anchor>> {
5977        let (excerpt_id, _, buffer) = self.as_singleton()?;
5978        let outline = buffer.outline(theme)?;
5979        Some(Outline::new(
5980            outline
5981                .items
5982                .into_iter()
5983                .flat_map(|item| {
5984                    Some(OutlineItem {
5985                        depth: item.depth,
5986                        range: self.anchor_in_excerpt(*excerpt_id, item.range.start)?
5987                            ..self.anchor_in_excerpt(*excerpt_id, item.range.end)?,
5988                        text: item.text,
5989                        highlight_ranges: item.highlight_ranges,
5990                        name_ranges: item.name_ranges,
5991                        body_range: item.body_range.and_then(|body_range| {
5992                            Some(
5993                                self.anchor_in_excerpt(*excerpt_id, body_range.start)?
5994                                    ..self.anchor_in_excerpt(*excerpt_id, body_range.end)?,
5995                            )
5996                        }),
5997                        annotation_range: item.annotation_range.and_then(|annotation_range| {
5998                            Some(
5999                                self.anchor_in_excerpt(*excerpt_id, annotation_range.start)?
6000                                    ..self.anchor_in_excerpt(*excerpt_id, annotation_range.end)?,
6001                            )
6002                        }),
6003                    })
6004                })
6005                .collect(),
6006        ))
6007    }
6008
6009    pub fn symbols_containing<T: ToOffset>(
6010        &self,
6011        offset: T,
6012        theme: Option<&SyntaxTheme>,
6013    ) -> Option<(BufferId, Vec<OutlineItem<Anchor>>)> {
6014        let anchor = self.anchor_before(offset);
6015        let excerpt_id = anchor.excerpt_id;
6016        let excerpt = self.excerpt(excerpt_id)?;
6017        Some((
6018            excerpt.buffer_id,
6019            excerpt
6020                .buffer
6021                .symbols_containing(anchor.text_anchor, theme)
6022                .into_iter()
6023                .flatten()
6024                .flat_map(|item| {
6025                    Some(OutlineItem {
6026                        depth: item.depth,
6027                        range: self.anchor_in_excerpt(excerpt_id, item.range.start)?
6028                            ..self.anchor_in_excerpt(excerpt_id, item.range.end)?,
6029                        text: item.text,
6030                        highlight_ranges: item.highlight_ranges,
6031                        name_ranges: item.name_ranges,
6032                        body_range: item.body_range.and_then(|body_range| {
6033                            Some(
6034                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6035                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6036                            )
6037                        }),
6038                        annotation_range: item.annotation_range.and_then(|body_range| {
6039                            Some(
6040                                self.anchor_in_excerpt(excerpt_id, body_range.start)?
6041                                    ..self.anchor_in_excerpt(excerpt_id, body_range.end)?,
6042                            )
6043                        }),
6044                    })
6045                })
6046                .collect(),
6047        ))
6048    }
6049
6050    fn excerpt_locator_for_id(&self, id: ExcerptId) -> &Locator {
6051        if id == ExcerptId::min() {
6052            Locator::min_ref()
6053        } else if id == ExcerptId::max() {
6054            Locator::max_ref()
6055        } else {
6056            let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6057            cursor.seek(&id, Bias::Left, &());
6058            if let Some(entry) = cursor.item() {
6059                if entry.id == id {
6060                    return &entry.locator;
6061                }
6062            }
6063            panic!("invalid excerpt id {:?}", id)
6064        }
6065    }
6066
6067    /// Returns the locators referenced by the given excerpt IDs, sorted by locator.
6068    fn excerpt_locators_for_ids(
6069        &self,
6070        ids: impl IntoIterator<Item = ExcerptId>,
6071    ) -> SmallVec<[Locator; 1]> {
6072        let mut sorted_ids = ids.into_iter().collect::<SmallVec<[_; 1]>>();
6073        sorted_ids.sort_unstable();
6074        let mut locators = SmallVec::new();
6075
6076        while sorted_ids.last() == Some(&ExcerptId::max()) {
6077            sorted_ids.pop();
6078            if let Some(mapping) = self.excerpt_ids.last() {
6079                locators.push(mapping.locator.clone());
6080            }
6081        }
6082
6083        let mut sorted_ids = sorted_ids.into_iter().dedup().peekable();
6084        if sorted_ids.peek() == Some(&ExcerptId::min()) {
6085            sorted_ids.next();
6086            if let Some(mapping) = self.excerpt_ids.first() {
6087                locators.push(mapping.locator.clone());
6088            }
6089        }
6090
6091        let mut cursor = self.excerpt_ids.cursor::<ExcerptId>(&());
6092        for id in sorted_ids {
6093            if cursor.seek_forward(&id, Bias::Left, &()) {
6094                locators.push(cursor.item().unwrap().locator.clone());
6095            } else {
6096                panic!("invalid excerpt id {:?}", id);
6097            }
6098        }
6099
6100        locators.sort_unstable();
6101        locators
6102    }
6103
6104    pub fn buffer_id_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<BufferId> {
6105        Some(self.excerpt(excerpt_id)?.buffer_id)
6106    }
6107
6108    pub fn buffer_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<&BufferSnapshot> {
6109        Some(&self.excerpt(excerpt_id)?.buffer)
6110    }
6111
6112    pub fn range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<Point>> {
6113        let mut cursor = self
6114            .excerpts
6115            .cursor::<(Option<&Locator>, ExcerptDimension<Point>)>(&());
6116        let locator = self.excerpt_locator_for_id(excerpt_id);
6117        if cursor.seek(&Some(locator), Bias::Left, &()) {
6118            let start = cursor.start().1.clone();
6119            let end = cursor.end(&()).1;
6120            let mut diff_transforms = self
6121                .diff_transforms
6122                .cursor::<(ExcerptDimension<Point>, OutputDimension<Point>)>(&());
6123            diff_transforms.seek(&start, Bias::Left, &());
6124            let overshoot = start.0 - diff_transforms.start().0.0;
6125            let start = diff_transforms.start().1.0 + overshoot;
6126            diff_transforms.seek(&end, Bias::Right, &());
6127            let overshoot = end.0 - diff_transforms.start().0.0;
6128            let end = diff_transforms.start().1.0 + overshoot;
6129            Some(start..end)
6130        } else {
6131            None
6132        }
6133    }
6134
6135    pub fn buffer_range_for_excerpt(&self, excerpt_id: ExcerptId) -> Option<Range<text::Anchor>> {
6136        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6137        let locator = self.excerpt_locator_for_id(excerpt_id);
6138        if cursor.seek(&Some(locator), Bias::Left, &()) {
6139            if let Some(excerpt) = cursor.item() {
6140                return Some(excerpt.range.context.clone());
6141            }
6142        }
6143        None
6144    }
6145
6146    fn excerpt(&self, excerpt_id: ExcerptId) -> Option<&Excerpt> {
6147        let mut cursor = self.excerpts.cursor::<Option<&Locator>>(&());
6148        let locator = self.excerpt_locator_for_id(excerpt_id);
6149        cursor.seek(&Some(locator), Bias::Left, &());
6150        if let Some(excerpt) = cursor.item() {
6151            if excerpt.id == excerpt_id {
6152                return Some(excerpt);
6153            }
6154        }
6155        None
6156    }
6157
6158    /// Returns the excerpt containing range and its offset start within the multibuffer or none if `range` spans multiple excerpts
6159    pub fn excerpt_containing<T: ToOffset>(&self, range: Range<T>) -> Option<MultiBufferExcerpt> {
6160        let range = range.start.to_offset(self)..range.end.to_offset(self);
6161        let mut cursor = self.cursor::<usize>();
6162        cursor.seek(&range.start);
6163
6164        let start_excerpt = cursor.excerpt()?;
6165        if range.end != range.start {
6166            cursor.seek_forward(&range.end);
6167            if cursor.excerpt()?.id != start_excerpt.id {
6168                return None;
6169            }
6170        }
6171
6172        cursor.seek_to_start_of_current_excerpt();
6173        let region = cursor.region()?;
6174        let offset = region.range.start;
6175        let buffer_offset = region.buffer_range.start;
6176        let excerpt_offset = cursor.excerpts.start().clone();
6177        Some(MultiBufferExcerpt {
6178            diff_transforms: cursor.diff_transforms,
6179            excerpt: start_excerpt,
6180            offset,
6181            buffer_offset,
6182            excerpt_offset,
6183        })
6184    }
6185
6186    pub fn selections_in_range<'a>(
6187        &'a self,
6188        range: &'a Range<Anchor>,
6189        include_local: bool,
6190    ) -> impl 'a + Iterator<Item = (ReplicaId, bool, CursorShape, Selection<Anchor>)> {
6191        let mut cursor = self.excerpts.cursor::<ExcerptSummary>(&());
6192        let start_locator = self.excerpt_locator_for_id(range.start.excerpt_id);
6193        let end_locator = self.excerpt_locator_for_id(range.end.excerpt_id);
6194        cursor.seek(start_locator, Bias::Left, &());
6195        cursor
6196            .take_while(move |excerpt| excerpt.locator <= *end_locator)
6197            .flat_map(move |excerpt| {
6198                let mut query_range = excerpt.range.context.start..excerpt.range.context.end;
6199                if excerpt.id == range.start.excerpt_id {
6200                    query_range.start = range.start.text_anchor;
6201                }
6202                if excerpt.id == range.end.excerpt_id {
6203                    query_range.end = range.end.text_anchor;
6204                }
6205
6206                excerpt
6207                    .buffer
6208                    .selections_in_range(query_range, include_local)
6209                    .flat_map(move |(replica_id, line_mode, cursor_shape, selections)| {
6210                        selections.map(move |selection| {
6211                            let mut start = Anchor {
6212                                buffer_id: Some(excerpt.buffer_id),
6213                                excerpt_id: excerpt.id,
6214                                text_anchor: selection.start,
6215                                diff_base_anchor: None,
6216                            };
6217                            let mut end = Anchor {
6218                                buffer_id: Some(excerpt.buffer_id),
6219                                excerpt_id: excerpt.id,
6220                                text_anchor: selection.end,
6221                                diff_base_anchor: None,
6222                            };
6223                            if range.start.cmp(&start, self).is_gt() {
6224                                start = range.start;
6225                            }
6226                            if range.end.cmp(&end, self).is_lt() {
6227                                end = range.end;
6228                            }
6229
6230                            (
6231                                replica_id,
6232                                line_mode,
6233                                cursor_shape,
6234                                Selection {
6235                                    id: selection.id,
6236                                    start,
6237                                    end,
6238                                    reversed: selection.reversed,
6239                                    goal: selection.goal,
6240                                },
6241                            )
6242                        })
6243                    })
6244            })
6245    }
6246
6247    pub fn show_headers(&self) -> bool {
6248        self.show_headers
6249    }
6250
6251    pub fn diff_for_buffer_id(&self, buffer_id: BufferId) -> Option<&BufferDiffSnapshot> {
6252        self.diffs.get(&buffer_id)
6253    }
6254}
6255
6256#[cfg(any(test, feature = "test-support"))]
6257impl MultiBufferSnapshot {
6258    pub fn random_byte_range(&self, start_offset: usize, rng: &mut impl rand::Rng) -> Range<usize> {
6259        let end = self.clip_offset(rng.gen_range(start_offset..=self.len()), Bias::Right);
6260        let start = self.clip_offset(rng.gen_range(start_offset..=end), Bias::Right);
6261        start..end
6262    }
6263
6264    #[cfg(any(test, feature = "test-support"))]
6265    fn check_invariants(&self) {
6266        let excerpts = self.excerpts.items(&());
6267        let excerpt_ids = self.excerpt_ids.items(&());
6268
6269        for (ix, excerpt) in excerpts.iter().enumerate() {
6270            if ix == 0 {
6271                if excerpt.locator <= Locator::min() {
6272                    panic!("invalid first excerpt locator {:?}", excerpt.locator);
6273                }
6274            } else if excerpt.locator <= excerpts[ix - 1].locator {
6275                panic!("excerpts are out-of-order: {:?}", excerpts);
6276            }
6277        }
6278
6279        for (ix, entry) in excerpt_ids.iter().enumerate() {
6280            if ix == 0 {
6281                if entry.id.cmp(&ExcerptId::min(), &self).is_le() {
6282                    panic!("invalid first excerpt id {:?}", entry.id);
6283                }
6284            } else if entry.id <= excerpt_ids[ix - 1].id {
6285                panic!("excerpt ids are out-of-order: {:?}", excerpt_ids);
6286            }
6287        }
6288
6289        if self.diff_transforms.summary().input != self.excerpts.summary().text {
6290            panic!(
6291                "incorrect input summary. expected {:?}, got {:?}. transforms: {:+?}",
6292                self.excerpts.summary().text.len,
6293                self.diff_transforms.summary().input,
6294                self.diff_transforms.items(&()),
6295            );
6296        }
6297
6298        let mut prev_transform: Option<&DiffTransform> = None;
6299        for item in self.diff_transforms.iter() {
6300            if let DiffTransform::BufferContent {
6301                summary,
6302                inserted_hunk_info,
6303            } = item
6304            {
6305                if let Some(DiffTransform::BufferContent {
6306                    inserted_hunk_info: prev_inserted_hunk_info,
6307                    ..
6308                }) = prev_transform
6309                {
6310                    if *inserted_hunk_info == *prev_inserted_hunk_info {
6311                        panic!(
6312                            "multiple adjacent buffer content transforms with is_inserted_hunk = {inserted_hunk_info:?}. transforms: {:+?}",
6313                            self.diff_transforms.items(&())
6314                        );
6315                    }
6316                }
6317                if summary.len == 0 && !self.is_empty() {
6318                    panic!("empty buffer content transform");
6319                }
6320            }
6321            prev_transform = Some(item);
6322        }
6323    }
6324}
6325
6326impl<'a, D> MultiBufferCursor<'a, D>
6327where
6328    D: TextDimension + Ord + Sub<D, Output = D>,
6329{
6330    fn seek(&mut self, position: &D) {
6331        self.cached_region.take();
6332        self.diff_transforms
6333            .seek(&OutputDimension(*position), Bias::Right, &());
6334        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0.0 {
6335            self.diff_transforms.prev(&());
6336        }
6337
6338        let mut excerpt_position = self.diff_transforms.start().1.0;
6339        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6340            let overshoot = *position - self.diff_transforms.start().0.0;
6341            excerpt_position.add_assign(&overshoot);
6342        }
6343
6344        self.excerpts
6345            .seek(&ExcerptDimension(excerpt_position), Bias::Right, &());
6346        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6347            self.excerpts.prev(&());
6348        }
6349    }
6350
6351    fn seek_forward(&mut self, position: &D) {
6352        self.cached_region.take();
6353        self.diff_transforms
6354            .seek_forward(&OutputDimension(*position), Bias::Right, &());
6355        if self.diff_transforms.item().is_none() && *position == self.diff_transforms.start().0.0 {
6356            self.diff_transforms.prev(&());
6357        }
6358
6359        let overshoot = *position - self.diff_transforms.start().0.0;
6360        let mut excerpt_position = self.diff_transforms.start().1.0;
6361        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6362            excerpt_position.add_assign(&overshoot);
6363        }
6364
6365        self.excerpts
6366            .seek_forward(&ExcerptDimension(excerpt_position), Bias::Right, &());
6367        if self.excerpts.item().is_none() && excerpt_position == self.excerpts.start().0 {
6368            self.excerpts.prev(&());
6369        }
6370    }
6371
6372    fn next_excerpt(&mut self) {
6373        self.excerpts.next(&());
6374        self.seek_to_start_of_current_excerpt();
6375    }
6376
6377    fn prev_excerpt(&mut self) {
6378        self.excerpts.prev(&());
6379        self.seek_to_start_of_current_excerpt();
6380    }
6381
6382    fn seek_to_start_of_current_excerpt(&mut self) {
6383        self.cached_region.take();
6384        self.diff_transforms
6385            .seek(self.excerpts.start(), Bias::Left, &());
6386        if self.diff_transforms.end(&()).1 == *self.excerpts.start()
6387            && self.diff_transforms.start().1 < *self.excerpts.start()
6388            && self.diff_transforms.next_item().is_some()
6389        {
6390            self.diff_transforms.next(&());
6391        }
6392    }
6393
6394    fn next(&mut self) {
6395        self.cached_region.take();
6396        match self.diff_transforms.end(&()).1.cmp(&self.excerpts.end(&())) {
6397            cmp::Ordering::Less => self.diff_transforms.next(&()),
6398            cmp::Ordering::Greater => self.excerpts.next(&()),
6399            cmp::Ordering::Equal => {
6400                self.diff_transforms.next(&());
6401                if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6402                    || self.diff_transforms.item().is_none()
6403                {
6404                    self.excerpts.next(&());
6405                } else if let Some(DiffTransform::DeletedHunk { hunk_info, .. }) =
6406                    self.diff_transforms.item()
6407                {
6408                    if self
6409                        .excerpts
6410                        .item()
6411                        .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id)
6412                    {
6413                        self.excerpts.next(&());
6414                    }
6415                }
6416            }
6417        }
6418    }
6419
6420    fn prev(&mut self) {
6421        self.cached_region.take();
6422        match self.diff_transforms.start().1.cmp(self.excerpts.start()) {
6423            cmp::Ordering::Less => self.excerpts.prev(&()),
6424            cmp::Ordering::Greater => self.diff_transforms.prev(&()),
6425            cmp::Ordering::Equal => {
6426                self.diff_transforms.prev(&());
6427                if self.diff_transforms.start().1 < *self.excerpts.start()
6428                    || self.diff_transforms.item().is_none()
6429                {
6430                    self.excerpts.prev(&());
6431                }
6432            }
6433        }
6434    }
6435
6436    fn region(&mut self) -> Option<MultiBufferRegion<'a, D>> {
6437        if self.cached_region.is_none() {
6438            self.cached_region = self.build_region();
6439        }
6440        self.cached_region.clone()
6441    }
6442
6443    fn is_at_start_of_excerpt(&mut self) -> bool {
6444        if self.diff_transforms.start().1 > *self.excerpts.start() {
6445            return false;
6446        } else if self.diff_transforms.start().1 < *self.excerpts.start() {
6447            return true;
6448        }
6449
6450        self.diff_transforms.prev(&());
6451        let prev_transform = self.diff_transforms.item();
6452        self.diff_transforms.next(&());
6453
6454        prev_transform.map_or(true, |next_transform| {
6455            matches!(next_transform, DiffTransform::BufferContent { .. })
6456        })
6457    }
6458
6459    fn is_at_end_of_excerpt(&mut self) -> bool {
6460        if self.diff_transforms.end(&()).1 < self.excerpts.end(&()) {
6461            return false;
6462        } else if self.diff_transforms.end(&()).1 > self.excerpts.end(&())
6463            || self.diff_transforms.item().is_none()
6464        {
6465            return true;
6466        }
6467
6468        let next_transform = self.diff_transforms.next_item();
6469        next_transform.map_or(true, |next_transform| match next_transform {
6470            DiffTransform::BufferContent { .. } => true,
6471            DiffTransform::DeletedHunk { hunk_info, .. } => self
6472                .excerpts
6473                .item()
6474                .map_or(false, |excerpt| excerpt.id != hunk_info.excerpt_id),
6475        })
6476    }
6477
6478    fn main_buffer_position(&self) -> Option<D> {
6479        let excerpt = self.excerpts.item()?;
6480        let buffer = &excerpt.buffer;
6481        let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6482        let mut buffer_start = buffer_context_start;
6483        let overshoot = self.diff_transforms.end(&()).1.0 - self.excerpts.start().0;
6484        buffer_start.add_assign(&overshoot);
6485        Some(buffer_start)
6486    }
6487
6488    fn build_region(&self) -> Option<MultiBufferRegion<'a, D>> {
6489        let excerpt = self.excerpts.item()?;
6490        match self.diff_transforms.item()? {
6491            DiffTransform::DeletedHunk {
6492                buffer_id,
6493                base_text_byte_range,
6494                has_trailing_newline,
6495                hunk_info,
6496                ..
6497            } => {
6498                let diff = self.diffs.get(&buffer_id)?;
6499                let buffer = diff.base_text();
6500                let mut rope_cursor = buffer.as_rope().cursor(0);
6501                let buffer_start = rope_cursor.summary::<D>(base_text_byte_range.start);
6502                let buffer_range_len = rope_cursor.summary::<D>(base_text_byte_range.end);
6503                let mut buffer_end = buffer_start;
6504                buffer_end.add_assign(&buffer_range_len);
6505                let start = self.diff_transforms.start().0.0;
6506                let end = self.diff_transforms.end(&()).0.0;
6507                return Some(MultiBufferRegion {
6508                    buffer,
6509                    excerpt,
6510                    has_trailing_newline: *has_trailing_newline,
6511                    is_main_buffer: false,
6512                    diff_hunk_status: Some(DiffHunkStatus::deleted(
6513                        hunk_info.hunk_secondary_status,
6514                    )),
6515                    buffer_range: buffer_start..buffer_end,
6516                    range: start..end,
6517                });
6518            }
6519            DiffTransform::BufferContent {
6520                inserted_hunk_info, ..
6521            } => {
6522                let buffer = &excerpt.buffer;
6523                let buffer_context_start = excerpt.range.context.start.summary::<D>(buffer);
6524
6525                let mut start = self.diff_transforms.start().0.0;
6526                let mut buffer_start = buffer_context_start;
6527                if self.diff_transforms.start().1 < *self.excerpts.start() {
6528                    let overshoot = self.excerpts.start().0 - self.diff_transforms.start().1.0;
6529                    start.add_assign(&overshoot);
6530                } else {
6531                    let overshoot = self.diff_transforms.start().1.0 - self.excerpts.start().0;
6532                    buffer_start.add_assign(&overshoot);
6533                }
6534
6535                let mut end;
6536                let mut buffer_end;
6537                let has_trailing_newline;
6538                if self.diff_transforms.end(&()).1.0 < self.excerpts.end(&()).0 {
6539                    let overshoot = self.diff_transforms.end(&()).1.0 - self.excerpts.start().0;
6540                    end = self.diff_transforms.end(&()).0.0;
6541                    buffer_end = buffer_context_start;
6542                    buffer_end.add_assign(&overshoot);
6543                    has_trailing_newline = false;
6544                } else {
6545                    let overshoot = self.excerpts.end(&()).0 - self.diff_transforms.start().1.0;
6546                    end = self.diff_transforms.start().0.0;
6547                    end.add_assign(&overshoot);
6548                    buffer_end = excerpt.range.context.end.summary::<D>(buffer);
6549                    has_trailing_newline = excerpt.has_trailing_newline;
6550                };
6551
6552                Some(MultiBufferRegion {
6553                    buffer,
6554                    excerpt,
6555                    has_trailing_newline,
6556                    is_main_buffer: true,
6557                    diff_hunk_status: inserted_hunk_info
6558                        .map(|info| DiffHunkStatus::added(info.hunk_secondary_status)),
6559                    buffer_range: buffer_start..buffer_end,
6560                    range: start..end,
6561                })
6562            }
6563        }
6564    }
6565
6566    fn excerpt(&self) -> Option<&'a Excerpt> {
6567        self.excerpts.item()
6568    }
6569}
6570
6571impl History {
6572    fn start_transaction(&mut self, now: Instant) -> Option<TransactionId> {
6573        self.transaction_depth += 1;
6574        if self.transaction_depth == 1 {
6575            let id = self.next_transaction_id.tick();
6576            self.undo_stack.push(Transaction {
6577                id,
6578                buffer_transactions: Default::default(),
6579                first_edit_at: now,
6580                last_edit_at: now,
6581                suppress_grouping: false,
6582            });
6583            Some(id)
6584        } else {
6585            None
6586        }
6587    }
6588
6589    fn end_transaction(
6590        &mut self,
6591        now: Instant,
6592        buffer_transactions: HashMap<BufferId, TransactionId>,
6593    ) -> bool {
6594        assert_ne!(self.transaction_depth, 0);
6595        self.transaction_depth -= 1;
6596        if self.transaction_depth == 0 {
6597            if buffer_transactions.is_empty() {
6598                self.undo_stack.pop();
6599                false
6600            } else {
6601                self.redo_stack.clear();
6602                let transaction = self.undo_stack.last_mut().unwrap();
6603                transaction.last_edit_at = now;
6604                for (buffer_id, transaction_id) in buffer_transactions {
6605                    transaction
6606                        .buffer_transactions
6607                        .entry(buffer_id)
6608                        .or_insert(transaction_id);
6609                }
6610                true
6611            }
6612        } else {
6613            false
6614        }
6615    }
6616
6617    fn push_transaction<'a, T>(
6618        &mut self,
6619        buffer_transactions: T,
6620        now: Instant,
6621        cx: &Context<MultiBuffer>,
6622    ) where
6623        T: IntoIterator<Item = (&'a Entity<Buffer>, &'a language::Transaction)>,
6624    {
6625        assert_eq!(self.transaction_depth, 0);
6626        let transaction = Transaction {
6627            id: self.next_transaction_id.tick(),
6628            buffer_transactions: buffer_transactions
6629                .into_iter()
6630                .map(|(buffer, transaction)| (buffer.read(cx).remote_id(), transaction.id))
6631                .collect(),
6632            first_edit_at: now,
6633            last_edit_at: now,
6634            suppress_grouping: false,
6635        };
6636        if !transaction.buffer_transactions.is_empty() {
6637            self.undo_stack.push(transaction);
6638            self.redo_stack.clear();
6639        }
6640    }
6641
6642    fn finalize_last_transaction(&mut self) {
6643        if let Some(transaction) = self.undo_stack.last_mut() {
6644            transaction.suppress_grouping = true;
6645        }
6646    }
6647
6648    fn forget(&mut self, transaction_id: TransactionId) -> Option<Transaction> {
6649        if let Some(ix) = self
6650            .undo_stack
6651            .iter()
6652            .rposition(|transaction| transaction.id == transaction_id)
6653        {
6654            Some(self.undo_stack.remove(ix))
6655        } else if let Some(ix) = self
6656            .redo_stack
6657            .iter()
6658            .rposition(|transaction| transaction.id == transaction_id)
6659        {
6660            Some(self.redo_stack.remove(ix))
6661        } else {
6662            None
6663        }
6664    }
6665
6666    fn transaction(&self, transaction_id: TransactionId) -> Option<&Transaction> {
6667        self.undo_stack
6668            .iter()
6669            .find(|transaction| transaction.id == transaction_id)
6670            .or_else(|| {
6671                self.redo_stack
6672                    .iter()
6673                    .find(|transaction| transaction.id == transaction_id)
6674            })
6675    }
6676
6677    fn transaction_mut(&mut self, transaction_id: TransactionId) -> Option<&mut Transaction> {
6678        self.undo_stack
6679            .iter_mut()
6680            .find(|transaction| transaction.id == transaction_id)
6681            .or_else(|| {
6682                self.redo_stack
6683                    .iter_mut()
6684                    .find(|transaction| transaction.id == transaction_id)
6685            })
6686    }
6687
6688    fn pop_undo(&mut self) -> Option<&mut Transaction> {
6689        assert_eq!(self.transaction_depth, 0);
6690        if let Some(transaction) = self.undo_stack.pop() {
6691            self.redo_stack.push(transaction);
6692            self.redo_stack.last_mut()
6693        } else {
6694            None
6695        }
6696    }
6697
6698    fn pop_redo(&mut self) -> Option<&mut Transaction> {
6699        assert_eq!(self.transaction_depth, 0);
6700        if let Some(transaction) = self.redo_stack.pop() {
6701            self.undo_stack.push(transaction);
6702            self.undo_stack.last_mut()
6703        } else {
6704            None
6705        }
6706    }
6707
6708    fn remove_from_undo(&mut self, transaction_id: TransactionId) -> Option<&Transaction> {
6709        let ix = self
6710            .undo_stack
6711            .iter()
6712            .rposition(|transaction| transaction.id == transaction_id)?;
6713        let transaction = self.undo_stack.remove(ix);
6714        self.redo_stack.push(transaction);
6715        self.redo_stack.last()
6716    }
6717
6718    fn group(&mut self) -> Option<TransactionId> {
6719        let mut count = 0;
6720        let mut transactions = self.undo_stack.iter();
6721        if let Some(mut transaction) = transactions.next_back() {
6722            while let Some(prev_transaction) = transactions.next_back() {
6723                if !prev_transaction.suppress_grouping
6724                    && transaction.first_edit_at - prev_transaction.last_edit_at
6725                        <= self.group_interval
6726                {
6727                    transaction = prev_transaction;
6728                    count += 1;
6729                } else {
6730                    break;
6731                }
6732            }
6733        }
6734        self.group_trailing(count)
6735    }
6736
6737    fn group_until(&mut self, transaction_id: TransactionId) {
6738        let mut count = 0;
6739        for transaction in self.undo_stack.iter().rev() {
6740            if transaction.id == transaction_id {
6741                self.group_trailing(count);
6742                break;
6743            } else if transaction.suppress_grouping {
6744                break;
6745            } else {
6746                count += 1;
6747            }
6748        }
6749    }
6750
6751    fn group_trailing(&mut self, n: usize) -> Option<TransactionId> {
6752        let new_len = self.undo_stack.len() - n;
6753        let (transactions_to_keep, transactions_to_merge) = self.undo_stack.split_at_mut(new_len);
6754        if let Some(last_transaction) = transactions_to_keep.last_mut() {
6755            if let Some(transaction) = transactions_to_merge.last() {
6756                last_transaction.last_edit_at = transaction.last_edit_at;
6757            }
6758            for to_merge in transactions_to_merge {
6759                for (buffer_id, transaction_id) in &to_merge.buffer_transactions {
6760                    last_transaction
6761                        .buffer_transactions
6762                        .entry(*buffer_id)
6763                        .or_insert(*transaction_id);
6764                }
6765            }
6766        }
6767
6768        self.undo_stack.truncate(new_len);
6769        self.undo_stack.last().map(|t| t.id)
6770    }
6771}
6772
6773impl Excerpt {
6774    fn new(
6775        id: ExcerptId,
6776        locator: Locator,
6777        buffer_id: BufferId,
6778        buffer: BufferSnapshot,
6779        range: ExcerptRange<text::Anchor>,
6780        has_trailing_newline: bool,
6781    ) -> Self {
6782        Excerpt {
6783            id,
6784            locator,
6785            max_buffer_row: range.context.end.to_point(&buffer).row,
6786            text_summary: buffer
6787                .text_summary_for_range::<TextSummary, _>(range.context.to_offset(&buffer)),
6788            buffer_id,
6789            buffer,
6790            range,
6791            has_trailing_newline,
6792        }
6793    }
6794
6795    fn chunks_in_range(&self, range: Range<usize>, language_aware: bool) -> ExcerptChunks {
6796        let content_start = self.range.context.start.to_offset(&self.buffer);
6797        let chunks_start = content_start + range.start;
6798        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6799
6800        let footer_height = if self.has_trailing_newline
6801            && range.start <= self.text_summary.len
6802            && range.end > self.text_summary.len
6803        {
6804            1
6805        } else {
6806            0
6807        };
6808
6809        let content_chunks = self.buffer.chunks(chunks_start..chunks_end, language_aware);
6810
6811        ExcerptChunks {
6812            excerpt_id: self.id,
6813            content_chunks,
6814            footer_height,
6815        }
6816    }
6817
6818    fn seek_chunks(&self, excerpt_chunks: &mut ExcerptChunks, range: Range<usize>) {
6819        let content_start = self.range.context.start.to_offset(&self.buffer);
6820        let chunks_start = content_start + range.start;
6821        let chunks_end = content_start + cmp::min(range.end, self.text_summary.len);
6822        excerpt_chunks.content_chunks.seek(chunks_start..chunks_end);
6823        excerpt_chunks.footer_height = if self.has_trailing_newline
6824            && range.start <= self.text_summary.len
6825            && range.end > self.text_summary.len
6826        {
6827            1
6828        } else {
6829            0
6830        };
6831    }
6832
6833    fn clip_anchor(&self, text_anchor: text::Anchor) -> text::Anchor {
6834        if text_anchor
6835            .cmp(&self.range.context.start, &self.buffer)
6836            .is_lt()
6837        {
6838            self.range.context.start
6839        } else if text_anchor
6840            .cmp(&self.range.context.end, &self.buffer)
6841            .is_gt()
6842        {
6843            self.range.context.end
6844        } else {
6845            text_anchor
6846        }
6847    }
6848
6849    fn contains(&self, anchor: &Anchor) -> bool {
6850        Some(self.buffer_id) == anchor.buffer_id
6851            && self
6852                .range
6853                .context
6854                .start
6855                .cmp(&anchor.text_anchor, &self.buffer)
6856                .is_le()
6857            && self
6858                .range
6859                .context
6860                .end
6861                .cmp(&anchor.text_anchor, &self.buffer)
6862                .is_ge()
6863    }
6864
6865    /// The [`Excerpt`]'s start offset in its [`Buffer`]
6866    fn buffer_start_offset(&self) -> usize {
6867        self.range.context.start.to_offset(&self.buffer)
6868    }
6869
6870    /// The [`Excerpt`]'s end offset in its [`Buffer`]
6871    fn buffer_end_offset(&self) -> usize {
6872        self.buffer_start_offset() + self.text_summary.len
6873    }
6874}
6875
6876impl<'a> MultiBufferExcerpt<'a> {
6877    pub fn id(&self) -> ExcerptId {
6878        self.excerpt.id
6879    }
6880
6881    pub fn buffer_id(&self) -> BufferId {
6882        self.excerpt.buffer_id
6883    }
6884
6885    pub fn start_anchor(&self) -> Anchor {
6886        Anchor {
6887            buffer_id: Some(self.excerpt.buffer_id),
6888            excerpt_id: self.excerpt.id,
6889            text_anchor: self.excerpt.range.context.start,
6890            diff_base_anchor: None,
6891        }
6892    }
6893
6894    pub fn end_anchor(&self) -> Anchor {
6895        Anchor {
6896            buffer_id: Some(self.excerpt.buffer_id),
6897            excerpt_id: self.excerpt.id,
6898            text_anchor: self.excerpt.range.context.end,
6899            diff_base_anchor: None,
6900        }
6901    }
6902
6903    pub fn buffer(&self) -> &'a BufferSnapshot {
6904        &self.excerpt.buffer
6905    }
6906
6907    pub fn buffer_range(&self) -> Range<usize> {
6908        self.buffer_offset
6909            ..self
6910                .excerpt
6911                .range
6912                .context
6913                .end
6914                .to_offset(&self.excerpt.buffer.text)
6915    }
6916
6917    pub fn start_offset(&self) -> usize {
6918        self.offset
6919    }
6920
6921    /// Maps an offset within the [`MultiBuffer`] to an offset within the [`Buffer`]
6922    pub fn map_offset_to_buffer(&mut self, offset: usize) -> usize {
6923        self.map_range_to_buffer(offset..offset).start
6924    }
6925
6926    /// Maps a range within the [`MultiBuffer`] to a range within the [`Buffer`]
6927    pub fn map_range_to_buffer(&mut self, range: Range<usize>) -> Range<usize> {
6928        self.diff_transforms
6929            .seek(&OutputDimension(range.start), Bias::Right, &());
6930        let start = self.map_offset_to_buffer_internal(range.start);
6931        let end = if range.end > range.start {
6932            self.diff_transforms
6933                .seek_forward(&OutputDimension(range.end), Bias::Right, &());
6934            self.map_offset_to_buffer_internal(range.end)
6935        } else {
6936            start
6937        };
6938        start..end
6939    }
6940
6941    fn map_offset_to_buffer_internal(&self, offset: usize) -> usize {
6942        let mut excerpt_offset = self.diff_transforms.start().1.clone();
6943        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
6944            excerpt_offset.0 += offset - self.diff_transforms.start().0.0;
6945        };
6946        let offset_in_excerpt = excerpt_offset.0.saturating_sub(self.excerpt_offset.0);
6947        self.buffer_offset + offset_in_excerpt
6948    }
6949
6950    /// Map an offset within the [`Buffer`] to an offset within the [`MultiBuffer`]
6951    pub fn map_offset_from_buffer(&mut self, buffer_offset: usize) -> usize {
6952        self.map_range_from_buffer(buffer_offset..buffer_offset)
6953            .start
6954    }
6955
6956    /// Map a range within the [`Buffer`] to a range within the [`MultiBuffer`]
6957    pub fn map_range_from_buffer(&mut self, buffer_range: Range<usize>) -> Range<usize> {
6958        if buffer_range.start < self.buffer_offset {
6959            log::warn!(
6960                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6961            );
6962            return buffer_range;
6963        }
6964        let overshoot = buffer_range.start - self.buffer_offset;
6965        let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6966        self.diff_transforms.seek(&excerpt_offset, Bias::Right, &());
6967        if excerpt_offset.0 < self.diff_transforms.start().1.0 {
6968            log::warn!(
6969                "Attempting to map a range from a buffer offset that starts before the current buffer offset"
6970            );
6971            return buffer_range;
6972        }
6973        let overshoot = excerpt_offset.0 - self.diff_transforms.start().1.0;
6974        let start = self.diff_transforms.start().0.0 + overshoot;
6975
6976        let end = if buffer_range.end > buffer_range.start {
6977            let overshoot = buffer_range.end - self.buffer_offset;
6978            let excerpt_offset = ExcerptDimension(self.excerpt_offset.0 + overshoot);
6979            self.diff_transforms
6980                .seek_forward(&excerpt_offset, Bias::Right, &());
6981            let overshoot = excerpt_offset.0 - self.diff_transforms.start().1.0;
6982            self.diff_transforms.start().0.0 + overshoot
6983        } else {
6984            start
6985        };
6986
6987        start..end
6988    }
6989
6990    /// Returns true if the entirety of the given range is in the buffer's excerpt
6991    pub fn contains_buffer_range(&self, range: Range<usize>) -> bool {
6992        range.start >= self.excerpt.buffer_start_offset()
6993            && range.end <= self.excerpt.buffer_end_offset()
6994    }
6995
6996    pub fn max_buffer_row(&self) -> u32 {
6997        self.excerpt.max_buffer_row
6998    }
6999}
7000
7001impl ExcerptId {
7002    pub fn min() -> Self {
7003        Self(0)
7004    }
7005
7006    pub fn max() -> Self {
7007        Self(usize::MAX)
7008    }
7009
7010    pub fn to_proto(&self) -> u64 {
7011        self.0 as _
7012    }
7013
7014    pub fn from_proto(proto: u64) -> Self {
7015        Self(proto as _)
7016    }
7017
7018    pub fn cmp(&self, other: &Self, snapshot: &MultiBufferSnapshot) -> cmp::Ordering {
7019        let a = snapshot.excerpt_locator_for_id(*self);
7020        let b = snapshot.excerpt_locator_for_id(*other);
7021        a.cmp(b).then_with(|| self.0.cmp(&other.0))
7022    }
7023}
7024
7025impl From<ExcerptId> for usize {
7026    fn from(val: ExcerptId) -> Self {
7027        val.0
7028    }
7029}
7030
7031impl fmt::Debug for Excerpt {
7032    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
7033        f.debug_struct("Excerpt")
7034            .field("id", &self.id)
7035            .field("locator", &self.locator)
7036            .field("buffer_id", &self.buffer_id)
7037            .field("range", &self.range)
7038            .field("text_summary", &self.text_summary)
7039            .field("has_trailing_newline", &self.has_trailing_newline)
7040            .finish()
7041    }
7042}
7043
7044impl sum_tree::Item for Excerpt {
7045    type Summary = ExcerptSummary;
7046
7047    fn summary(&self, _cx: &()) -> Self::Summary {
7048        let mut text = self.text_summary;
7049        if self.has_trailing_newline {
7050            text += TextSummary::from("\n");
7051        }
7052        ExcerptSummary {
7053            excerpt_id: self.id,
7054            excerpt_locator: self.locator.clone(),
7055            widest_line_number: self.max_buffer_row,
7056            text,
7057        }
7058    }
7059}
7060
7061impl sum_tree::Item for ExcerptIdMapping {
7062    type Summary = ExcerptId;
7063
7064    fn summary(&self, _cx: &()) -> Self::Summary {
7065        self.id
7066    }
7067}
7068
7069impl sum_tree::KeyedItem for ExcerptIdMapping {
7070    type Key = ExcerptId;
7071
7072    fn key(&self) -> Self::Key {
7073        self.id
7074    }
7075}
7076
7077impl DiffTransform {
7078    fn hunk_info(&self) -> Option<DiffTransformHunkInfo> {
7079        match self {
7080            DiffTransform::DeletedHunk { hunk_info, .. } => Some(*hunk_info),
7081            DiffTransform::BufferContent {
7082                inserted_hunk_info, ..
7083            } => *inserted_hunk_info,
7084        }
7085    }
7086}
7087
7088impl sum_tree::Item for DiffTransform {
7089    type Summary = DiffTransformSummary;
7090
7091    fn summary(&self, _: &<Self::Summary as sum_tree::Summary>::Context) -> Self::Summary {
7092        match self {
7093            DiffTransform::BufferContent { summary, .. } => DiffTransformSummary {
7094                input: *summary,
7095                output: *summary,
7096            },
7097            DiffTransform::DeletedHunk { summary, .. } => DiffTransformSummary {
7098                input: TextSummary::default(),
7099                output: *summary,
7100            },
7101        }
7102    }
7103}
7104
7105impl DiffTransformSummary {
7106    fn excerpt_len(&self) -> ExcerptOffset {
7107        ExcerptOffset::new(self.input.len)
7108    }
7109}
7110
7111impl sum_tree::Summary for DiffTransformSummary {
7112    type Context = ();
7113
7114    fn zero(_: &Self::Context) -> Self {
7115        DiffTransformSummary {
7116            input: TextSummary::default(),
7117            output: TextSummary::default(),
7118        }
7119    }
7120
7121    fn add_summary(&mut self, summary: &Self, _: &Self::Context) {
7122        self.input += &summary.input;
7123        self.output += &summary.output;
7124    }
7125}
7126
7127impl sum_tree::Summary for ExcerptId {
7128    type Context = ();
7129
7130    fn zero(_cx: &()) -> Self {
7131        Default::default()
7132    }
7133
7134    fn add_summary(&mut self, other: &Self, _: &()) {
7135        *self = *other;
7136    }
7137}
7138
7139impl sum_tree::Summary for ExcerptSummary {
7140    type Context = ();
7141
7142    fn zero(_cx: &()) -> Self {
7143        Default::default()
7144    }
7145
7146    fn add_summary(&mut self, summary: &Self, _: &()) {
7147        debug_assert!(summary.excerpt_locator > self.excerpt_locator);
7148        self.excerpt_locator = summary.excerpt_locator.clone();
7149        self.text.add_summary(&summary.text, &());
7150        self.widest_line_number = cmp::max(self.widest_line_number, summary.widest_line_number);
7151    }
7152}
7153
7154impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptOffset {
7155    fn zero(_cx: &()) -> Self {
7156        Default::default()
7157    }
7158
7159    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7160        self.value += summary.text.len;
7161    }
7162}
7163
7164impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for ExcerptOffset {
7165    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7166        Ord::cmp(&self.value, &cursor_location.text.len)
7167    }
7168}
7169
7170impl<'a> sum_tree::SeekTarget<'a, ExcerptSummary, Option<&'a Locator>> for Locator {
7171    fn cmp(&self, cursor_location: &Option<&'a Locator>, _: &()) -> cmp::Ordering {
7172        Ord::cmp(&Some(self), cursor_location)
7173    }
7174}
7175
7176impl sum_tree::SeekTarget<'_, ExcerptSummary, ExcerptSummary> for Locator {
7177    fn cmp(&self, cursor_location: &ExcerptSummary, _: &()) -> cmp::Ordering {
7178        Ord::cmp(self, &cursor_location.excerpt_locator)
7179    }
7180}
7181
7182impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for ExcerptPoint {
7183    fn zero(_cx: &()) -> Self {
7184        Default::default()
7185    }
7186
7187    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7188        self.value += summary.text.lines;
7189    }
7190}
7191
7192impl<'a, D: TextDimension + Default> sum_tree::Dimension<'a, ExcerptSummary>
7193    for ExcerptDimension<D>
7194{
7195    fn zero(_: &()) -> Self {
7196        ExcerptDimension(D::default())
7197    }
7198
7199    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7200        self.0.add_assign(&D::from_text_summary(&summary.text))
7201    }
7202}
7203
7204impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<&'a Locator> {
7205    fn zero(_cx: &()) -> Self {
7206        Default::default()
7207    }
7208
7209    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7210        *self = Some(&summary.excerpt_locator);
7211    }
7212}
7213
7214impl<'a> sum_tree::Dimension<'a, ExcerptSummary> for Option<ExcerptId> {
7215    fn zero(_cx: &()) -> Self {
7216        Default::default()
7217    }
7218
7219    fn add_summary(&mut self, summary: &'a ExcerptSummary, _: &()) {
7220        *self = Some(summary.excerpt_id);
7221    }
7222}
7223
7224#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7225struct ExcerptDimension<T>(T);
7226
7227#[derive(Clone, PartialOrd, Ord, Eq, PartialEq, Debug)]
7228struct OutputDimension<T>(T);
7229
7230impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptOffset {
7231    fn zero(_: &()) -> Self {
7232        ExcerptOffset::new(0)
7233    }
7234
7235    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7236        self.value += summary.input.len;
7237    }
7238}
7239
7240impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptPoint {
7241    fn zero(_: &()) -> Self {
7242        ExcerptPoint::new(0, 0)
7243    }
7244
7245    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7246        self.value += summary.input.lines;
7247    }
7248}
7249
7250impl<D: TextDimension + Ord> sum_tree::SeekTarget<'_, DiffTransformSummary, DiffTransformSummary>
7251    for ExcerptDimension<D>
7252{
7253    fn cmp(&self, cursor_location: &DiffTransformSummary, _: &()) -> cmp::Ordering {
7254        Ord::cmp(&self.0, &D::from_text_summary(&cursor_location.input))
7255    }
7256}
7257
7258impl<D: TextDimension + Ord>
7259    sum_tree::SeekTarget<'_, DiffTransformSummary, (OutputDimension<D>, ExcerptDimension<D>)>
7260    for ExcerptDimension<D>
7261{
7262    fn cmp(
7263        &self,
7264        cursor_location: &(OutputDimension<D>, ExcerptDimension<D>),
7265        _: &(),
7266    ) -> cmp::Ordering {
7267        Ord::cmp(&self.0, &cursor_location.1.0)
7268    }
7269}
7270
7271impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for ExcerptDimension<D> {
7272    fn zero(_: &()) -> Self {
7273        ExcerptDimension(D::default())
7274    }
7275
7276    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7277        self.0.add_assign(&D::from_text_summary(&summary.input))
7278    }
7279}
7280
7281impl<'a, D: TextDimension> sum_tree::Dimension<'a, DiffTransformSummary> for OutputDimension<D> {
7282    fn zero(_: &()) -> Self {
7283        OutputDimension(D::default())
7284    }
7285
7286    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7287        self.0.add_assign(&D::from_text_summary(&summary.output))
7288    }
7289}
7290
7291impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for TextSummary {
7292    fn zero(_: &()) -> Self {
7293        TextSummary::default()
7294    }
7295
7296    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7297        *self += summary.output
7298    }
7299}
7300
7301impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for usize {
7302    fn zero(_: &()) -> Self {
7303        0
7304    }
7305
7306    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7307        *self += summary.output.len
7308    }
7309}
7310
7311impl<'a> sum_tree::Dimension<'a, DiffTransformSummary> for Point {
7312    fn zero(_: &()) -> Self {
7313        Point::new(0, 0)
7314    }
7315
7316    fn add_summary(&mut self, summary: &'a DiffTransformSummary, _: &()) {
7317        *self += summary.output.lines
7318    }
7319}
7320
7321impl MultiBufferRows<'_> {
7322    pub fn seek(&mut self, MultiBufferRow(row): MultiBufferRow) {
7323        self.point = Point::new(row, 0);
7324        self.cursor.seek(&self.point);
7325    }
7326}
7327
7328impl Iterator for MultiBufferRows<'_> {
7329    type Item = RowInfo;
7330
7331    fn next(&mut self) -> Option<Self::Item> {
7332        if self.is_empty && self.point.row == 0 {
7333            self.point += Point::new(1, 0);
7334            return Some(RowInfo {
7335                buffer_id: None,
7336                buffer_row: Some(0),
7337                multibuffer_row: Some(MultiBufferRow(0)),
7338                diff_status: None,
7339                expand_info: None,
7340            });
7341        }
7342
7343        let mut region = self.cursor.region()?;
7344        while self.point >= region.range.end {
7345            self.cursor.next();
7346            if let Some(next_region) = self.cursor.region() {
7347                region = next_region;
7348            } else {
7349                if self.point == self.cursor.diff_transforms.end(&()).0.0 {
7350                    let multibuffer_row = MultiBufferRow(self.point.row);
7351                    let last_excerpt = self
7352                        .cursor
7353                        .excerpts
7354                        .item()
7355                        .or(self.cursor.excerpts.prev_item())?;
7356                    let last_row = last_excerpt
7357                        .range
7358                        .context
7359                        .end
7360                        .to_point(&last_excerpt.buffer)
7361                        .row;
7362
7363                    let first_row = last_excerpt
7364                        .range
7365                        .context
7366                        .start
7367                        .to_point(&last_excerpt.buffer)
7368                        .row;
7369
7370                    let expand_info = if self.is_singleton {
7371                        None
7372                    } else {
7373                        let needs_expand_up = first_row == last_row
7374                            && last_row > 0
7375                            && !region.diff_hunk_status.is_some_and(|d| d.is_deleted());
7376                        let needs_expand_down = last_row < last_excerpt.buffer.max_point().row;
7377
7378                        if needs_expand_up && needs_expand_down {
7379                            Some(ExpandExcerptDirection::UpAndDown)
7380                        } else if needs_expand_up {
7381                            Some(ExpandExcerptDirection::Up)
7382                        } else if needs_expand_down {
7383                            Some(ExpandExcerptDirection::Down)
7384                        } else {
7385                            None
7386                        }
7387                        .map(|direction| ExpandInfo {
7388                            direction,
7389                            excerpt_id: last_excerpt.id,
7390                        })
7391                    };
7392                    self.point += Point::new(1, 0);
7393                    return Some(RowInfo {
7394                        buffer_id: Some(last_excerpt.buffer_id),
7395                        buffer_row: Some(last_row),
7396                        multibuffer_row: Some(multibuffer_row),
7397                        diff_status: None,
7398                        expand_info,
7399                    });
7400                } else {
7401                    return None;
7402                }
7403            };
7404        }
7405
7406        let overshoot = self.point - region.range.start;
7407        let buffer_point = region.buffer_range.start + overshoot;
7408        let expand_info = if self.is_singleton {
7409            None
7410        } else {
7411            let needs_expand_up = self.point.row == region.range.start.row
7412                && self.cursor.is_at_start_of_excerpt()
7413                && buffer_point.row > 0;
7414            let needs_expand_down = (region.excerpt.has_trailing_newline
7415                && self.point.row + 1 == region.range.end.row
7416                || !region.excerpt.has_trailing_newline && self.point.row == region.range.end.row)
7417                && self.cursor.is_at_end_of_excerpt()
7418                && buffer_point.row < region.buffer.max_point().row;
7419
7420            if needs_expand_up && needs_expand_down {
7421                Some(ExpandExcerptDirection::UpAndDown)
7422            } else if needs_expand_up {
7423                Some(ExpandExcerptDirection::Up)
7424            } else if needs_expand_down {
7425                Some(ExpandExcerptDirection::Down)
7426            } else {
7427                None
7428            }
7429            .map(|direction| ExpandInfo {
7430                direction,
7431                excerpt_id: region.excerpt.id,
7432            })
7433        };
7434
7435        let result = Some(RowInfo {
7436            buffer_id: Some(region.buffer.remote_id()),
7437            buffer_row: Some(buffer_point.row),
7438            multibuffer_row: Some(MultiBufferRow(self.point.row)),
7439            diff_status: region
7440                .diff_hunk_status
7441                .filter(|_| self.point < region.range.end),
7442            expand_info,
7443        });
7444        self.point += Point::new(1, 0);
7445        result
7446    }
7447}
7448
7449impl<'a> MultiBufferChunks<'a> {
7450    pub fn offset(&self) -> usize {
7451        self.range.start
7452    }
7453
7454    pub fn seek(&mut self, range: Range<usize>) {
7455        self.diff_transforms.seek(&range.end, Bias::Right, &());
7456        let mut excerpt_end = self.diff_transforms.start().1;
7457        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7458            let overshoot = range.end - self.diff_transforms.start().0;
7459            excerpt_end.value += overshoot;
7460        }
7461
7462        self.diff_transforms.seek(&range.start, Bias::Right, &());
7463        let mut excerpt_start = self.diff_transforms.start().1;
7464        if let Some(DiffTransform::BufferContent { .. }) = self.diff_transforms.item() {
7465            let overshoot = range.start - self.diff_transforms.start().0;
7466            excerpt_start.value += overshoot;
7467        }
7468
7469        self.seek_to_excerpt_offset_range(excerpt_start..excerpt_end);
7470        self.buffer_chunk.take();
7471        self.range = range;
7472    }
7473
7474    fn seek_to_excerpt_offset_range(&mut self, new_range: Range<ExcerptOffset>) {
7475        self.excerpt_offset_range = new_range.clone();
7476        self.excerpts.seek(&new_range.start, Bias::Right, &());
7477        if let Some(excerpt) = self.excerpts.item() {
7478            let excerpt_start = *self.excerpts.start();
7479            if let Some(excerpt_chunks) = self
7480                .excerpt_chunks
7481                .as_mut()
7482                .filter(|chunks| excerpt.id == chunks.excerpt_id)
7483            {
7484                excerpt.seek_chunks(
7485                    excerpt_chunks,
7486                    (self.excerpt_offset_range.start - excerpt_start).value
7487                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7488                );
7489            } else {
7490                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7491                    (self.excerpt_offset_range.start - excerpt_start).value
7492                        ..(self.excerpt_offset_range.end - excerpt_start).value,
7493                    self.language_aware,
7494                ));
7495            }
7496        } else {
7497            self.excerpt_chunks = None;
7498        }
7499    }
7500
7501    fn next_excerpt_chunk(&mut self) -> Option<Chunk<'a>> {
7502        loop {
7503            if self.excerpt_offset_range.is_empty() {
7504                return None;
7505            } else if let Some(chunk) = self.excerpt_chunks.as_mut()?.next() {
7506                self.excerpt_offset_range.start.value += chunk.text.len();
7507                return Some(chunk);
7508            } else {
7509                self.excerpts.next(&());
7510                let excerpt = self.excerpts.item()?;
7511                self.excerpt_chunks = Some(excerpt.chunks_in_range(
7512                    0..(self.excerpt_offset_range.end - *self.excerpts.start()).value,
7513                    self.language_aware,
7514                ));
7515            }
7516        }
7517    }
7518}
7519
7520impl<'a> Iterator for ReversedMultiBufferChunks<'a> {
7521    type Item = &'a str;
7522
7523    fn next(&mut self) -> Option<Self::Item> {
7524        let mut region = self.cursor.region()?;
7525        if self.offset == region.range.start {
7526            self.cursor.prev();
7527            region = self.cursor.region()?;
7528            let start_overshoot = self.start.saturating_sub(region.range.start);
7529            self.current_chunks = Some(region.buffer.reversed_chunks_in_range(
7530                region.buffer_range.start + start_overshoot..region.buffer_range.end,
7531            ));
7532        }
7533
7534        if self.offset == region.range.end && region.has_trailing_newline {
7535            self.offset -= 1;
7536            Some("\n")
7537        } else {
7538            let chunk = self.current_chunks.as_mut().unwrap().next()?;
7539            self.offset -= chunk.len();
7540            Some(chunk)
7541        }
7542    }
7543}
7544
7545impl<'a> Iterator for MultiBufferChunks<'a> {
7546    type Item = Chunk<'a>;
7547
7548    fn next(&mut self) -> Option<Chunk<'a>> {
7549        if self.range.start >= self.range.end {
7550            return None;
7551        }
7552        if self.range.start == self.diff_transforms.end(&()).0 {
7553            self.diff_transforms.next(&());
7554        }
7555
7556        let diff_transform_start = self.diff_transforms.start().0;
7557        let diff_transform_end = self.diff_transforms.end(&()).0;
7558        debug_assert!(self.range.start < diff_transform_end);
7559
7560        let diff_transform = self.diff_transforms.item()?;
7561        match diff_transform {
7562            DiffTransform::BufferContent { .. } => {
7563                let chunk = if let Some(chunk) = &mut self.buffer_chunk {
7564                    chunk
7565                } else {
7566                    let chunk = self.next_excerpt_chunk().unwrap();
7567                    self.buffer_chunk.insert(chunk)
7568                };
7569
7570                let chunk_end = self.range.start + chunk.text.len();
7571                let diff_transform_end = diff_transform_end.min(self.range.end);
7572
7573                if diff_transform_end < chunk_end {
7574                    let (before, after) =
7575                        chunk.text.split_at(diff_transform_end - self.range.start);
7576                    self.range.start = diff_transform_end;
7577                    chunk.text = after;
7578                    Some(Chunk {
7579                        text: before,
7580                        ..chunk.clone()
7581                    })
7582                } else {
7583                    self.range.start = chunk_end;
7584                    self.buffer_chunk.take()
7585                }
7586            }
7587            DiffTransform::DeletedHunk {
7588                buffer_id,
7589                base_text_byte_range,
7590                has_trailing_newline,
7591                ..
7592            } => {
7593                let base_text_start =
7594                    base_text_byte_range.start + self.range.start - diff_transform_start;
7595                let base_text_end =
7596                    base_text_byte_range.start + self.range.end - diff_transform_start;
7597                let base_text_end = base_text_end.min(base_text_byte_range.end);
7598
7599                let mut chunks = if let Some((_, mut chunks)) = self
7600                    .diff_base_chunks
7601                    .take()
7602                    .filter(|(id, _)| id == buffer_id)
7603                {
7604                    if chunks.range().start != base_text_start || chunks.range().end < base_text_end
7605                    {
7606                        chunks.seek(base_text_start..base_text_end);
7607                    }
7608                    chunks
7609                } else {
7610                    let base_buffer = &self.diffs.get(&buffer_id)?.base_text();
7611                    base_buffer.chunks(base_text_start..base_text_end, self.language_aware)
7612                };
7613
7614                let chunk = if let Some(chunk) = chunks.next() {
7615                    self.range.start += chunk.text.len();
7616                    self.diff_base_chunks = Some((*buffer_id, chunks));
7617                    chunk
7618                } else {
7619                    debug_assert!(has_trailing_newline);
7620                    self.range.start += "\n".len();
7621                    Chunk {
7622                        text: "\n",
7623                        ..Default::default()
7624                    }
7625                };
7626                Some(chunk)
7627            }
7628        }
7629    }
7630}
7631
7632impl MultiBufferBytes<'_> {
7633    fn consume(&mut self, len: usize) {
7634        self.range.start += len;
7635        self.chunk = &self.chunk[len..];
7636
7637        if !self.range.is_empty() && self.chunk.is_empty() {
7638            if let Some(chunk) = self.excerpt_bytes.as_mut().and_then(|bytes| bytes.next()) {
7639                self.chunk = chunk;
7640            } else if self.has_trailing_newline {
7641                self.has_trailing_newline = false;
7642                self.chunk = b"\n";
7643            } else {
7644                self.cursor.next();
7645                if let Some(region) = self.cursor.region() {
7646                    let mut excerpt_bytes = region.buffer.bytes_in_range(
7647                        region.buffer_range.start
7648                            ..(region.buffer_range.start + self.range.end - region.range.start)
7649                                .min(region.buffer_range.end),
7650                    );
7651                    self.chunk = excerpt_bytes.next().unwrap_or(&[]);
7652                    self.excerpt_bytes = Some(excerpt_bytes);
7653                    self.has_trailing_newline =
7654                        region.has_trailing_newline && self.range.end >= region.range.end;
7655                    if self.chunk.is_empty() && self.has_trailing_newline {
7656                        self.has_trailing_newline = false;
7657                        self.chunk = b"\n";
7658                    }
7659                }
7660            }
7661        }
7662    }
7663}
7664
7665impl<'a> Iterator for MultiBufferBytes<'a> {
7666    type Item = &'a [u8];
7667
7668    fn next(&mut self) -> Option<Self::Item> {
7669        let chunk = self.chunk;
7670        if chunk.is_empty() {
7671            None
7672        } else {
7673            self.consume(chunk.len());
7674            Some(chunk)
7675        }
7676    }
7677}
7678
7679impl io::Read for MultiBufferBytes<'_> {
7680    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7681        let len = cmp::min(buf.len(), self.chunk.len());
7682        buf[..len].copy_from_slice(&self.chunk[..len]);
7683        if len > 0 {
7684            self.consume(len);
7685        }
7686        Ok(len)
7687    }
7688}
7689
7690impl io::Read for ReversedMultiBufferBytes<'_> {
7691    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
7692        let len = cmp::min(buf.len(), self.chunk.len());
7693        buf[..len].copy_from_slice(&self.chunk[..len]);
7694        buf[..len].reverse();
7695        if len > 0 {
7696            self.range.end -= len;
7697            self.chunk = &self.chunk[..self.chunk.len() - len];
7698            if !self.range.is_empty() && self.chunk.is_empty() {
7699                if let Some(chunk) = self.chunks.next() {
7700                    self.chunk = chunk.as_bytes();
7701                }
7702            }
7703        }
7704        Ok(len)
7705    }
7706}
7707
7708impl<'a> Iterator for ExcerptChunks<'a> {
7709    type Item = Chunk<'a>;
7710
7711    fn next(&mut self) -> Option<Self::Item> {
7712        if let Some(chunk) = self.content_chunks.next() {
7713            return Some(chunk);
7714        }
7715
7716        if self.footer_height > 0 {
7717            let text = unsafe { str::from_utf8_unchecked(&NEWLINES[..self.footer_height]) };
7718            self.footer_height = 0;
7719            return Some(Chunk {
7720                text,
7721                ..Default::default()
7722            });
7723        }
7724
7725        None
7726    }
7727}
7728
7729impl ToOffset for Point {
7730    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7731        snapshot.point_to_offset(*self)
7732    }
7733}
7734
7735impl ToOffset for usize {
7736    #[track_caller]
7737    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7738        assert!(*self <= snapshot.len(), "offset is out of range");
7739        *self
7740    }
7741}
7742
7743impl ToOffset for OffsetUtf16 {
7744    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7745        snapshot.offset_utf16_to_offset(*self)
7746    }
7747}
7748
7749impl ToOffset for PointUtf16 {
7750    fn to_offset<'a>(&self, snapshot: &MultiBufferSnapshot) -> usize {
7751        snapshot.point_utf16_to_offset(*self)
7752    }
7753}
7754
7755impl ToOffsetUtf16 for OffsetUtf16 {
7756    fn to_offset_utf16(&self, _snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7757        *self
7758    }
7759}
7760
7761impl ToOffsetUtf16 for usize {
7762    fn to_offset_utf16(&self, snapshot: &MultiBufferSnapshot) -> OffsetUtf16 {
7763        snapshot.offset_to_offset_utf16(*self)
7764    }
7765}
7766
7767impl ToPoint for usize {
7768    fn to_point<'a>(&self, snapshot: &MultiBufferSnapshot) -> Point {
7769        snapshot.offset_to_point(*self)
7770    }
7771}
7772
7773impl ToPoint for Point {
7774    fn to_point<'a>(&self, _: &MultiBufferSnapshot) -> Point {
7775        *self
7776    }
7777}
7778
7779impl ToPointUtf16 for usize {
7780    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7781        snapshot.offset_to_point_utf16(*self)
7782    }
7783}
7784
7785impl ToPointUtf16 for Point {
7786    fn to_point_utf16<'a>(&self, snapshot: &MultiBufferSnapshot) -> PointUtf16 {
7787        snapshot.point_to_point_utf16(*self)
7788    }
7789}
7790
7791impl ToPointUtf16 for PointUtf16 {
7792    fn to_point_utf16<'a>(&self, _: &MultiBufferSnapshot) -> PointUtf16 {
7793        *self
7794    }
7795}
7796
7797impl From<ExcerptId> for EntityId {
7798    fn from(id: ExcerptId) -> Self {
7799        EntityId::from(id.0 as u64)
7800    }
7801}
7802
7803pub fn build_excerpt_ranges<T>(
7804    buffer: &BufferSnapshot,
7805    ranges: &[Range<T>],
7806    context_line_count: u32,
7807) -> (Vec<ExcerptRange<Point>>, Vec<usize>)
7808where
7809    T: text::ToPoint,
7810{
7811    let max_point = buffer.max_point();
7812    let mut range_counts = Vec::new();
7813    let mut excerpt_ranges = Vec::new();
7814    let mut range_iter = ranges
7815        .iter()
7816        .map(|range| range.start.to_point(buffer)..range.end.to_point(buffer))
7817        .peekable();
7818    while let Some(range) = range_iter.next() {
7819        let excerpt_start = Point::new(range.start.row.saturating_sub(context_line_count), 0);
7820        let row = (range.end.row + context_line_count).min(max_point.row);
7821        let mut excerpt_end = Point::new(row, buffer.line_len(row));
7822
7823        let mut ranges_in_excerpt = 1;
7824
7825        while let Some(next_range) = range_iter.peek() {
7826            if next_range.start.row <= excerpt_end.row + context_line_count {
7827                let row = (next_range.end.row + context_line_count).min(max_point.row);
7828                excerpt_end = Point::new(row, buffer.line_len(row));
7829
7830                ranges_in_excerpt += 1;
7831                range_iter.next();
7832            } else {
7833                break;
7834            }
7835        }
7836
7837        excerpt_ranges.push(ExcerptRange {
7838            context: excerpt_start..excerpt_end,
7839            primary: range,
7840        });
7841        range_counts.push(ranges_in_excerpt);
7842    }
7843
7844    (excerpt_ranges, range_counts)
7845}